Resolved Out-of-Warranty Issues

Problem: Foam blowing out the vents, temperature control of the heating/cooling air no longer works.
Dealer: My garage
Date: March-2017
The flapper that diverts air through or around the heater core, and the flapper that switches between recirculated and outside air, are covered with foam. When the foam starts to dry-rot due to age, it falls off and starts blowing out of the vents. Even worse, the metal plate to which the foam attaches is not solid but rather has multiple large opening in it, meaning that air blows through the flaps and is no longer diverted. So hot and cold air are always mixed, and inside/outside air is always mixed, and the air temperature can no longer be adjusted. I used this method to repair/recover the flaps, which just required removing the radio and is much easier than removing the entire dash and HVAC unit.

Problem: Bolts that hold the convertible top receiver to the windshield header fell out. Cast brass nut inserts split and failed.
Dealer: My garage
Date: November-2016
All of the bolts that go into the windshield header are likely to eventually fail. This is because the nuts inside the windshield are cast brass and don’t hold up over time. The only way to access the nuts is to remove the windshield. To permanently resolve the problem, drill-out and extract the brass nuts and then install M6x1.0 x 15mm long rivet nut inserts using a Rivet Nut installer tool. Full installation instructions here.

Problem: Random electrical problems, electrical components not working, gauges acting strange, HVAC acting strange, engine would die when brake pedal depressed or when placed in reverse.
Dealer: My garage
Date: June-2016
Lots of weird random electrical problems. Caused by the replacement ignition switch not passing sufficient current. Was previously replaced June 2004; replacement part had more severe failure mode than original component. Problem permanently fixed by installing new ignition assembly casting and new-style ignition switch used in 2004 Boxsters. Installed Steering Lock Assembly with Ignition Switch part number 996-347-017-07-M100. Installation instructions here.

Problem: Windows would roll down about 3 inches while driving
Dealer: My garage
Date: June-2006
The convertible top micro-switch was being tripped when driving over bumps. The switch inaccurately sensed that the convertible top latch was open. Replacing the micro-switch did not fix the problem. The micro-switch had to be modified to add extra padding (a piece of electrical tape) around switch button, making sure the top latch fully engaged the switch when it was closed.

Problem: Large amounts of white smoke out of the exhaust after hard, high engine speed acceleration followed by immediate closed throttle.
Dealer: My garage
Date: Aug-2005
Engine oil level over filled. This caused the Closed Crankcase Ventilation system to deposit engine oil mist into the intake manifold when there were high levels of vacuum (closed throttle at high engine speeds). Solution: lower oil level, clean out intake manifold.

Problem: Ignition switch will not return to the Run position from the Start position, resulting in no accessory power.
Dealer: My garage
Date: June-2004
Ordered a replacement for electrical portion of ignition switch from Autohaus, part number 4A0 905 849. Update: do not install this part – it will fail in a different way than the original part. See updated failure/replacement above for June-2016.

Problem: Convertible top not closing properly
Dealer: Carlton’s Garage
Date: Jan-2004
The top seams would not line-up properly with the rails above the side windows, just as it was before. I tightened the tension cables for the top, located at the sides of the compartment below the back window. Also adjusted a small arm (held in place by two torx screws) located near the side window frame, accessible when the top is 70% open. Problem resolved.

Resolved Warranty Issues

Problem: Abnormal wear of the convertible top fabric
Dealer: Beechmont Porsche
Date: Jun-03
The top was experiencing abnormal wear in the fabric at the outer edges of where the wear window fold occurs. Top replaced under warranty.
Problem: Convertible top not closing properly
Dealer: Beechmont Porsche
Date: Jan-00
The top would not close properly above the drivers window. This problem occurred the first time I closed the top on the day I brought the car home.

Problem: Storage compartment metal strip
Dealer: Beechmont Porsche
Date: Jan-00
The metal strip in the storage compartment below the convertible top fell out.

Problem: Calibration Update (Vehicle Speed Correction)
Dealer: Beechmont Porsche
Date: Jan-00
The indicated vehicle speed is approximately 5% higher than the actual vehicle speed. The odometer reading was approximately 5% higher than the actual miles traveled. Porsche released a new calibration that corrected the problem. Click here for more info on the problem from my fuel economy page.

Note: The correct speedometer reading for 2.5L engine is 42 miles/hour in 3rd gear at 3000 rpm.

Problem: Drivers window would roll-down on it’s own after parking the car
Dealer: Tom Wood Porsche
Date: Jun-00
Several time, I returned to my car to find the drivers window rolled down about 6 inches. The motor for the window was replaced and the problem has been resolved.Problem: Replaced seal on fuel filler cap
Dealer: Tom Wood Porsche
Date: Jun-00
As part of a campaign from Porsche, the seal on the fuel filler cap was replaced during a warranty visit. I did not notice a problem with the filler cap.

Porsche 986 Boxster Idle Problem:

Engine surges and starts to die when returning to idle
Dealers: Beechmont Porsche, Tom Wood Porsche
Service Dates: 1/00, 6/00, 7/00, 5/01
Status: Still not fixed
Link to PCA Question/Answer for similar problem

Idle Problem Update:

After 4 trips to 2 different dealers, the problem is still unresolved. Due to the extremely poor treatment I received at Tom Wood Porsche in Indianapolis, I decided to work exclusively with Beechmont Porsche in Cincinnati, OH.In June of 2000, I learned of a “DME upgrade” for the engine control software/calibration that would solve the problem. After 2 trips to Tom Wood, they finally tried to perform the update, realized that they didn’t know how to do a full DME recalibration, and called the regional service representative.

They were told by the regional service representative that it wasn’t new software, but rather a reinstallation of the same old software. It was previously believed that the initial software installation at the factory was incomplete and that reprogramming would correct the problem. This is no longer believed to be the case. According the the regional service rep, the “DME upgrade” didn’t solve the problem on the last 3 cars with which he had been involved. I’m still waiting to have this problem resolved.

The vehicle was since taken to Beechmont Porsche in Cincinnati, OH and extensive testing was performed and a factory representative was involved. The conclusion was that a new calibration needed to be developed for the engine computer. I have since been informed that a new calibration will not be made available and that there is no way to resolve this problem.

Idle Problem Description:

Click here for an MPEG movie showing the problem. (290 Kb)
The engine speed will droop well below the intended 800 RPM after depressing the clutch when returning to idle. The speed will droop as low as 600 RPM, at which point the engine starts to stumble and die before recovering and overshooting to 1000 RPM and then returning to the standard 800 RPM idle speed. This problem happens almost every time the car returns to idle, to varying degrees, when the air conditioner is activated by the climate control system.

Idle Problem Duplication:

The problem occurs under many different driving conditions but can be consistently duplicated using the following procedure:

  1. Coolant temperature 170 degrees F or above.
  2. Ambient temperature of approximately 80 degrees F or above
  3. Air conditioner turned ON to lowest setting
  4. Drive in second gear at about 2000 RPM
  5. Lift foot from throttle and allow engine to motor (coast) down to about 1200 RPM.
  6. Depress the clutch when engine speed reaches approximately 1200 RPM
  7. Idle speed will drop to as low as 600 RPM, the engine will shake, stutter, and start to die
  8. Engine will then recover by overshooting to 1000 RPM and then returning to 800 RPM (normal idle speed)

Picture From Step 7: Engine speed drops to 600 RPM and starts to shutter and die after depressing the clutch while driving. (Engine speed of just below 700 RPM shown in the picture – it was hard to capture 600 RPM with the digital camera.)

Idle Problem Duplication – Secondary situation when the problem occurs:

1. Make a sharp turn to either the left or the right with the clutch pedal depressed.

2. The power steering apparently adds excessive load to the engine, and engine speed droops to about 600 RPM, starts to die, then over-compensates to 1000 RPM, and recovers to the desired speed of 800 RPM.

Graph of Idle Problem:

Porsche has identified this problem to be engine computer calibration related. Here is a list of other possible causes I was told were ruled out by Porsche:

1. Idle Air Bypass Valve Hysteresis (Sticking)

2. Mass Air Flow Sensor – Inaccurate at low engine speed transient conditions

3. Intake Manifold Pressure Sensor, Intake Manifold Temperature Sensor, or Throttle Position Sensor in-range failure/out-of-specification – could effect air flow prediction calculation (not likely, Mass Air Flow Sensor should perform this measurement)

4. Higher than expected accessory load from the air conditioner, etc.

5. Intake manifold air leak (not likely, would result in higher idle speeds, not lower)

6. Software expecting low accessory loads and/or gain is too slow to react at higher accessory loads. (not likely, problem would be much more wide-spread?)

7. Fuel injection quantity too low or Oxygen Sensor incorrectly reading Air/Fuel ratio (not likely a fuel system problem, most likely air-control related)

Dealer Experiences:

Beechmont Porsche – Cincinnati, OH: 2 visits – A rating

  • Provided a Rental Car free of charge
  • Technically competent
  • Researched factory service updates to find relevance to my problems
  • Very friendly, good service
  • The Dealership placed a follow-up / survey call to determine my satisfaction.

Tom Wood – Indianapolis, IN: 2 visits – D rating

  • Charged me for the rental car
  • Technician knew next to nothing about the Porsche Electronic Service Tool
  • Did not fix all of my problems after the first visit but told me that they did
  • Did not fully investigate my complaints that they did not understand how to resolve
  • The service manager did not call me back after my second visit to let me know what he had found from the factory service representative in order to solve my problem.
  • The Dealership placed only one follow-up / survey phone call — but they left a message and never called back. They did not call me after my first visit at all. I was never able to give them my opinion of their service.

Related Links:

Instructions for Replacing Air Filter

Instructions for Replacing Cabin Filter

Instructions for Headlight Removal

Instructions on how to replace Rear Main Seal (RMS) on a Porsche M96 engine


  1. Hello,

    I too recently began to experience this idling problem with my 2000 boxster. I noticed that after I replaced the engine air filter, disconnected the battery, and reconnected it, the ECU was either reset or erased, causing me to lose many presets such as automatic window up or down with one press of the window buttons. I also noticed that my car began idling in a strange manner, fluctuating between 1000 and 500 RPM. I would therefore attribute such an issue to the onboard ECU losing or corrupting the data that controls engine timing and whatnot.

    1. Hi.
      Can you please tell me how you replaced the air filter? I bought one and do not want the dealer to charge me a fortune for something I can do myself.



    2. Author

      Dave, remove the mat and engine cover under the convertible top (four anchors requiring a 1/2 turn.) The air filter is behind the drivers seat under these covers. The air intake goes from the scoop in front of the rear wheel, through the filter box, and into the engine. Slide the filter up and replace it. Pretty simple and no tools required.

  2. hi i have a boxster that seams to have a poor idle showing a sute from the exhaust also after removing all 6x spark plugs noticed that 3x plug were black or running rich but only on right hand bank the other 3x plugs have a normal colour any ideas what this prob could be many thank

  3. Just a guess, but Oxygen Sensors are very unreliable and they do control each bank independent of the other. I’d start with the pre-catalyst oxygen sensor on the side that is running rich.

  4. Hi Carlton,

    It seems I have the exact same idle problem as you do on my 2004 Boxster which I bought in January 2007 with less than 20k miles on it. Of course, I only noticed the idle problem in March 2007 when I started using the AC. (In case you’re wondering why I would start using the AC so early in spring, I live in Dubai, UAE and it gets warm early here.)

    I’m wondering if you’ve finally managed to fix the idle problem. If not, do you know if it causes any long-term damage to the engine? Or is it just an irritant that one will have to live with if one was unlucky enough to buy one of the affected Boxsters?

    I’m just beginning my effort to try and fix this problem. If I meet with any success, I’ll be certain to keep you updated.



    1. Just change the serpentine belt…that should take car of the problem…..with ac and idealing…

  5. Ranesh,

    I have not managed to completely eliminate the problem. I did minimize it by removing the idle bypass valve and cleaning. This is a small, electrically -ontrolled rotary gate valve that controls the amount of air that is let around the throttle plate at idle. So, if engine speed starts to drop, the valve opens up, allows more air, which in turn allows more fuel, which finally raised engine idle speed. My idle bypass valve had a lot of carbon deposits on it that I manged to remove. I thought I’d found the final solution, but it did not totally eliminate the problem.

    You may want to give this a try. As I remember, it was very easy to remove (2 bolts) but there was a paper gasket that was not very durable. Also, my Boxster is a version that does not have the electronic throttle pedal / throttle plate. Your’s does have the electronic throttle controls (Porsche calls it E-gas.) I’m not sure, but the electronic throttle plate may completely eliminate the idle bypass valve (since the engine computer controls the throttle plate, it may eliminate the need for a second air flow control device.)

    This has been the one frustrating problem I’ve had with my Boxster that I’ve not been able to solve. I’m sorry to hear that you are having it as well. Best of luck resolving it and please let me know what you find.


  6. Hi Carlton,

    Thank you for your prompt response. After reading your story and doing some research around the net, I don’t have much confidence in ever being able to resolve the problem. From what I have read on the problem at PCNA has not even admitted that there is a problem. Customer service in my country is a lot worse than it is in the US and I doubt they’ll do anything about it here.

    While my problem is essentially identical to yours, there is a slight difference in the RPM at which it occurs. My normal idle RPM is 700 (maybe even a whisker under 700), not 800 as is the case in your Boxster. It goes down to 600 (exactly as yours) but recovers and overshoots to 800 (not 1,000 like yours) before settling back to the normal 700.

    When you say that cleaning the idle bypass valve minimised the problem, do you mean it reduced the severity (RPMs drop less and then overshoot less) or the frequency of the problem? Also, do you know if the problem causes any long-term damage to the engine? If not, I guess one can simply learn to live with it.

    Thanks again.


  7. Ranesh,

    Sorry I wasn’t more clear. Cleaning the valve did not change the frequency of occurrence but it did minimized the severity (the RPMs did not drop as drastically or overshoot quite so much.) As for long-term durability, there are zero concerns there; it will have no long-term impact on durability. Trust me, I’ve had the problem for 8 years! It’s no different than taping the throttle plate or, really, even from normal idle. Annoying? Yes. Damaging? No.

    One major change that would help eliminate the problem would be the upgrade to a larger displacement engine. More displacement means more torque at idle and less susceptibility to accessory load fluctuations. Yes, I’d love to have 3.8L 911 engine dropped in my Boxster, but I have to be realistic: it’s never gonna happen!

  8. paul
    I to have the same problem with my 2002 boxter s
    i will contact porsche service centre tomorrow,
    date;19/12/07 to see if they know more
    they seem very helpful in the past

  9. 2000 boxster s 3.2 with a similer surge problem at idle. Frustrated in Pittsburgh. No apparant sure fire fix. Mass air flow replaced five thousand miles ago. Don’t remember how long it has been happening. Car has 20K, no previous work, not faults to guide us. Any clues would be helpful.

  10. FYI,
    I have a 98 boxster with 50,000 miles on it that has had the same excact idle problem your are encountering with newer model boxters. I had one of the best Porsche mechanics in Las vegas work on the problem for several weeks to no luck. I have had the car for 7 years and is still running great other than the idle problem once the summer hits in Vegas and the AC goes on. My mechanic swears he will find a fix for the problem as no one seems to have an answer for him. I will keep you posted if he does.

  11. Carlos, Thanks for the reply. I still don’t have a solution either so please let me know if you find anything.

  12. Has anyone tried a new ICV rather than just cleaning it?

  13. I had the same problem with a 1998 Boxster. Took the car in many times during first few years complaining of the low rpm shutter when engine was hunting for idle. Recently (February of 2009), I took the car in complaining of pungent gas smell at startup. The mechanic recommended replacing the Mass Air Sensor. I agreed, thinking it may affect the shutter which I had learned to drive around. Guess what – the shutter is gone. No hesitation or tendancy to die at low rpm. Contacted Porsche North America, they said that since it was replaced by a non-dealer, they would do nothing. DROVE THE CAR FOR 11 YEARS WITH THIS ISSUE!! I think the car is now more responsive.

    1. Ric, thanks for the comment. I’m going to try a Mass Air Sensor replacement as well. The dealership claimed that they tried this and it resulted in no change to the problem, but I’m not sure I trust their capabilities. Hopefully this will eliminate my problem; it’s been 11 years for me also.

  14. It has been quite some time since my last inquiry about the engine surge, I believe dec. 07.

    The idle is the same. I remember that the idle went haywire after the installation of the mass air flow sensor.

    Is there some type of special mapping that should occur after the sensor is replaced? It does seem to be linked to the sensor.

    Any information would be much appreciated. I love this car, otherwise it is faultless.

  15. Hello Carlton and Everyone that has this issue,

    I have the same problem with my 2000 boxster but mines has gotten worse. My engine RPM flactuates on idle non-stop. It goes down to around 600 then shoots to 800 then 700 then repeats continuosly. I have taken it to many shops but no one seems to know what the problem is. I replaced so many things already that I might as well build a boxster from scatch. I replaced the Mass Air Flow sensor to no avail. I was thinking that it might be a vac leak but from what I have been reading here it sounds like a softaware issue that will never be resolved. Good Luck to all.


  16. My 2000 boxter hade this same problem, im not sure what i did to resolve this problem i spent a day going over the whole top of the engine… egr valve, throttle body, plugs, fuel regulator, pcv, injector o-rings, air idle control. etc. basicly anything that was on the top of the engine and removable. dealers are great but they wont provide a service like this at any reasonable cost….. im quite confident it was either my intake manifold gaskets or my fuel injector o-rings. good luck

  17. I have a 1999 Boxster 2.5L with 60,000miles that has a similar problem.
    It does all the things mentioned above, but also idles quite high at times. between 1000 & 1500 rpm. After driving it for a while it seems to return to perfect idle. Other times it’s quite erratic and will stall when the revs are too low.
    The less I drive it the more symptomatic it is.
    Since it is my weekend car, she doesn’t get much time on the road. I would love to get to th ebottom of this.
    Any thoughts?

  18. hi my boxster is a 2000 with all of the above
    why cant Porsche fix this problem I’m going to try and clean out the mas flow sensor and throttle body and give everything a good clean we will see if it makes any difference here’s hoping

  19. I have a 1998 Porsche Boxster. Can you test the Oxygen Sensors? and how?

    1. Author

      Basically, if you have an O2 sensor fault, the sensor is bad. If you don’t, it’s probably OK.

      The engine computer does diagnostics and can detect when the sensor is bad (when the car is coasting and the engine is in a no-fuel situation, the O2 level in the exhaust is 20.95%, i.e. earth atmosphere. If the sensor is reading any other level in this condition, either the sensor is bad or you are on another planet. The computer assumes the former and lights a light.)

      There are 2 sets of sensors, one before the catalytic converter and one after. The one before is used to run the engine and the one after is used to detect catalytic converter failures. The one before the cats is where the problems usually are.

  20. Hi all, I had the annoying problem of irratic idling, one porsche ‘specialist’ told me it was an 02 sensor, another said it was the MAF, so I looked around for proof of their diagnosis and found that you can try disconnecting the MAF and see if the problem goes away, I tried this and it reduced it but did not remove the problem, I then tried cleaning it whilst I had the engine cover off, still didnt remove the problem so thought it might not be the MAF, so i went further up the line, removed the intake pipe to the throttle body and the butterfly was covered in crap at least 3-4mm so I removed the whole thing and cleaned it with some carb cleaner, replaced and turned the key – music to my ears a static idle of just below 800, test drove and no stuttering slowing for junctions etc all seemed good.
    a week later the idle is still fine however today I experienced some restriction when I got to around 3-4000rpm in any gear, the temperaturre was -4degreesC and the engine was not completely warm, any suggesons? this cant be related to the throttle body can it?

  21. Being in the “Porsche” business, I would like to put my two cents in to the problem.
    The Boxster as well as all new OBDII equipped Porsches are Energy Hungry cars. The idling drop is actually a drop in voltage. Alternators on these cars are too weak to provide enough power. Driving with the lights on in traffic can increase the RPM fluctuation if the battery is not up to the snuff. These cars can wear out the battery in less than two years, especially if it is not driven often during the day time. In fact, the car starts does not mean the battery is capable of handling quick load and unload. It is like a domino effect if the RPM drops due to the low voltage, the DME will immediately in-rich the mixture- RPM goes up. Any load on the circuit, like brake lights at the stop, AC running, cooling fans activating, turning steering wheel (load increase on the engine) will reduce the voltage for the DME and spark consumption increasing load on the battery. Pick-up and drivability is greatly affected. I can not recommend the fix, however, changing the battery more often does help. I can only say that this particular problem plagued most of GMC ODBII equipped trucks up to (I believe) 2001. The solution was to install high voltage alternator and deep-cycle battery.

    1. I have a 2000 Boxster 2.7L with 88,900 miles. I had this happen to me yesterday after I changed the battery, but went away after driving about 20 miles. The engine was dropping from 1000 to just under 500, then back up repetitiously. It never did that before, even on my dead battery! (Which only lasted 2 years!!) It’s back to a smooth idle now around 800 RPM’s. I was stumped, which is why I looked online to see if it is common. What happened for me I guess was the computer resetting? I even called my dealership about it and they had no clue why it immediately starting doing it after putting in a new battery.

      Has anyone else seen or heard of this happening before after installing a new battery?

    2. This is very true. I found on my 98 Boxster the hard and frustraiting way. The codes said lean on both banks, so everything said to check for vaccum leaks. I did all of that and still same codes and Check engine light still came on. Was checking the car over and notice the battery was over 6 yrs old so bought a new one. Drove the car for almost a week and no light, Drove to work with the heater, radio and lights on and the check engine light came back on…Checked the voltage over the weekend and had a drop in voltage, now comes the chasing down what is drawing the voltage while the car is off and parked…new headache.(plan to start with the aftermarket radio that the previous owner installed..pulled it out and a rats nest of wires going everywhere(good place to start)

    3. Author


      Usually the code for “lean in both banks” means that the mass air flow sensor in the intake needs to be replaced. This is pretty common on Boxsters and 911s.

      1. I took it to a shop that I stumbled on while driving and they hooked it up to the computer and checked everything out at first they were saying the same thing as you, that it was the mass air flow sensor. Then he noticed that there was no signal from one bank of O2 sensors. After checking into that further he found the relay was sticking, so he forced it to open and close a few times and I have not had the problem for over 2 months of daily driving.

  22. I bought recently a 2000 Boxster 2,7 l with 58000 km (36000miles) that has an irregular idle which goes from 400 rpm to 800 rpm all the time regardless of AC or other electric functions.
    I changed the battery, but still same problem. Porsche dealer did not find answer to uneven idle.
    I read all solutions recommendations, but I am unable to figure it out.

    Would appreciate any new insight.

  23. Hi, my partner currently owns a 3.2 Boxter. there is massive amounts of white smoke coming out of the exhaust on start up and also when driving. It has just come out of the garage after having the breather pipes cleaned and new plugs. the compression test was done and all is normal. preformance is still good but it still smokes really bad. am at the end of my tether with this and its costing lots evertime its in the garage. please help with any solutions. ps, parking on a slope dont work, as recomended by porsche.

    1. Author

      If you have white smoke, then you have oil in cylinders. White smoke on start-up is nothing to worry about, as that is inherent with the flat 6 engine design, but while driving well after start-up, that is a concern. Make sure the engine is not over-full with oil as this will cause white smoke. If that isn’t the issue, and compression is fine, then it is a more complicated problem and I’m not sure what it might be.

  24. When my 02 Boxster did this it was a bad AOS (air-oil separator), a relatively common problem, and not really serious unless you don’t fix it (oil sucked into intake and then into cylinders in any substantial quantity can cause real damage). Shops sometimes want $700-1000 to replace this. I bought the part and did it myself (difficult to access but not really that complicated) for way less. I believe there are instructions on Pelican parts or other places. Good luck.

  25. I have a similar idle problem (rpm drop when leaving from stop)…have not replaced any parts yet. If I disconnect the battery for a few minutes, (resetting the computer) everything get’s cleaned up. Eventually, the problem shows up again, but the car runs GREAT for a while! It could be alternator charge and/or maybe california fuel quality causing the computer to down grade timing and such?

  26. hey guys, i have a 2002 boxster. for the past few days, i have noticed a strong gas smell. i took it to a local mechanic and they can’t seem to find the a gas leak. they agree that there is definitely a gas odor. they thought it may be the catalytic converters. any thoughts?

    1. I recently bought a used 2002 boxster, everything seemed good, driving daily.. weather turned cold and wet, car sits in garage. I have noticed if car sits for ~4+ days, for the first few minutes I get a fairly strong gas odor… goes away in a few minutes. Haven’t had time to do any real investigation except look and see if I saw gas leaking… Any ideas?

      1. You might want to look at your fuel injectors, maybe one of them is having a leak in the fuel injector seal. You have to replace the injecto, you can’t fix the seal.

    2. Author

      I experience this as well. I don’t think it’s anything to worry about. I believe it’s because flat 6 engines have horizontal pistons, leading to oil (and potentially any unburned fuel) to accumulate in the cylinder bores, as opposed to draining back into the oil pan (past the piston rings) as in V and inline engines.

    3. I am advised this problem is probably one of the fuel injector seals, which means the fuel injector will have to be replaced. I havea 2002 Boxster with the same problem.

  27. Hi

    I have a 1997 Porsche Boxster and have found that while waiting at lights the idle fluctuates down to 800 rpm and can get quite erratic. This happened for two days then i started getting white smoke when waiting at lights. The car drives fine, then i got home switched it off then several hours later back on and a large amount of white smoke came out and i haven’t switched it back on since then. Not sure what to do.

    1. White smoke could indicate that you are getting water in one of the cyclinders, possibly you will need a head gasket. Just for your information, blue smoke means oil in a cylinder and black smoke means it’s running too rich, too much gas, not enough air.

  28. Hi Fellas,

    Just started reading this thread. Been informative and want to thank Carlton for starting it and those who’ve contributed.

    I have a 1999 2.5L that constantly hunts between 1300-2000 rpms. Started after I replaced the passenger-side catalytic converter and the pre and post Cat O2 sensors (the old Cat had a hole that got progressively larger). I unplugged the battery to reset the computer but the problem persisted. Received a CEl (P0506 – Idle Air Control System RPM Lower Than Expected).

    Things tried or trying:
    -Replaced air filter – no change
    -Cleaned MAF and will be cleaning the throttle body and Idle Control Valve.
    -Will have to take it to the dealer to check for a vacuum leak if the aforementioned don’t work.

    Seems like many here have had these idle problems for a long time. Just wondering if anyone has a thought as to why my idle hunting would start right after replacing the Cat and 02 sensors?

    I’ll let everyone know if my attempted solutions work.


    1. Author

      Anthony, have you considered that the Idle Air Control valve is sticking? Mine had carbon deposites on it that caused it to stick. There’s an outside chance it’s the engine speed sensor, but not likely.

      1. Carlton,

        Thanks for your reply. I had a number of problems which delayed my attempt to remedy this “hunting” problem. I cleaned the throttle body to the best of my ability and cleaned as much of the carbon from the Idle Air Control Valve as I could get to ( I didn’t remove it from the throttle body because I didn’t have a replacement gasket). Unfortunately, the “hunting” problem continues. I’m not sure what options I have except to have it checked for a vacuum leak. This began when I replaced the catalytic converter and O2 sensors. The old exhaust had a hole just in front of the catalytic converter for quite some time. I wonder if driving with such a hole and then, in essence, sealing it by installing the new cat and O2 sensors has anything to do with it. I’m at a loss and hate to pay the dealer to “look” for a solution but I don’t know what else to do.

        Thanks again for your response.

      2. Author

        I’ve always believed this problem is related to the Mass Air Flow sensor and/or the O2 sensors. I wouldn’t think replacing the old sensors with new ones would cause the problem, but it’s a very particular system and anything is possible.

        To test, you can try disconnecting the O2 sensors and/or Mass Flow Sensor one at a time or in combo to see if that causes the problem to go away. (You’ll get fault codes while the sensors are unplugged.)

        Good luck!

  29. I will add another possibility to the mix although probably not as frequent. Camshaft sensor. 2003 Boxster S 50k miles, a/c running, summer in Florida, engine would intermittently stall and/or idle would fluctuate between 400 and 1000 when clutch was disengaged as coasting to a stop. Initially it would restart immediately, as the months went on it would restart but you could not rev the engine beyond 4k as it acted like you had hit the rev limiter. No codes to this point. I had it in the shop several times but because there were no codes and of course it never misbehaved for my mechanic they could not find the problem. They cleaned every ground on the car and trouble shooted ad nauseum. After about 9 months it finally threw a code. Bad camshaft position sensor. Problem solved.

    Now at 77k I have just had my clutch, flywheel etc and my IMS bearing replaced. IMS bearing replacement required the camshafts be retimed as the timing chains dropped off the camshaft gears. Now the intermittent engine stall has returned and again no codes. Although there is no problem with above 4k revs. Mechanic seems to believe that the computer just needs to settle in (adaptive throttle?). It is going back to the mechanic on Monday.

    1. Update on my 2003 Boxster S. The oil/air separator failed catastrophically when at the mechanic. It has been replaced and the car is now running well.

  30. Just wanted to say that I too have this issue. Shame that nobody has found a sure-fire fix after all this time. Since cleaning the ICV and intake has proven to at least help in some cases, perhaps I’ll try that this weekend.

  31. Hi,
    I have a 1998 Porky, same idling problem. This was a leak in the oil breather hose, it’s the black lolly pop item on the drivers side of the bay. It stank of oil and was running rough.

    Once this was replaced – it ran like a dream until I got a starter motor fitted – could then smell oil somewhere – it was coming from the coil packs – had this replaced. Oil now stopped but it does idle at 600 when stationary and engine light flashes. Feels like loss of compression –

    Still trying to find out but I can live with it as long as it doesn’t cost me anymore money 🙁

    Quick note – this will make you feel better – my roof doesn’t work, the central locking only works when driving and the paint looks like it’s been nuked.. but I love my porky :()

  32. Does my 2001 Porsche Boxter S VIN: WP0CB29821U662667 HAVE and electronic throttle control?? Important as I need a new Air Mass sensor and it is a diffferent part number for each application.

    1. Author

      Yes, it has the E-gas electronic throttle, starting in modle year 2000. You can test by pressing and releasing the throttle pedal with the car turned off. You’ll hear a sound behind you in the engine compartment if there is a cable moving the throttle. Otherwise, with an electronic throttle, you won’t.

  33. I wanted to let folks know that the problem was resolved. Turns out that the air filter is held in place but snaps at each corner. One corner was not secured, hense a vac leak. Once the vac leak was resolved, end of idle problem. Always check for vac leaks first before replacement.

  34. To all,
    I have a similar problem and have tried almost everything. My problem is slightly different.. When I try to start it up (on a hot day, I live in Miami and it is difficult to start it at noon), it cranks and cranks, and I have to give it gas until it eventually starts but it makes a weird screeching sound like the starter is sticking. A huge amount of white smoke comes out at start up. Then if I let go of the gas, it dies down again. Once the engine gets going a couple times, it normally runs fine. It seemed to be some kind of vacuum leak, especially since it makes a vacuum hose leak sound when I turn it off. Have not found any leaks though.

    I keep getting P1126 (Oxygen sensing adaptation, lower load range, cyl. 1-3) and P1124 (Fuel pump relay output stage, changed the relay and nothing) codes which seem to mean nothing because no mechanic knows exactly what part is causing it since they have tested the oxygen sensors. I have been stomped. Started checking out the carbon canister, the moved over to the air injection system. This is a very unique system. Where in other cars, there is a clear EGR valve (which tends to malfunction by either staying open or closed). This EGR valve supposely regulates how much exhaust is recirculated back into the system, and a wrong amount would cause idle problems. It would also cause that white smoke as well. The EGR valve symptoms tend to be confused for MAF sensor problems. The clear difference is the white smoke and what only seems to be like a clogged exhaust. That is the case for other cars. For the Porsche, there is no clear cut EGR valve. The air injection system is very complicated. There are check valves, change over valves, etc., but no EGR valve. If this EGR valve equivalent is determined, and I can clean it, unjam it, or replace it, I’m sure the problem would be fixed. It’s just crazy because no dealer or mechanic knows what’s wrong and every time they just make some shit up and charge me up the ass, so I stopped taking my car to the mechanic and got a service manual.

    I also think it could be the air pump, the secondary air injection system, or the carbon canister. Too bad each one is $1000+, so I haven’t bought any of them since it might not solve the problem. Would be nice if Porsche actually knew something about the car the designed.

    Someone at Porsche once told me that the EGR valve was called the EVAP canister purge valve. My guess is that once I change this it will be fixed. I will let you all know later this week.

  35. I read, what you write from Boxster. I looked after on the internet,and found a lots of problem whit it. What do you think, will I buy a Boxster or leave it? Oh,and I’am not rich.

    1. Tony, I’m not sure if you are saying that you found a particular car that has problems or are considering a Boxster in general. If you are looking at one that has problems, avoid it. They are very expensive to fix. Moreover, there are quite a few Boxsters out there that have good milage and no mechanical problems. Many owners “trade-up” so look around for the best you can find within your budget. Have a qualified mechanic it out. Many will say they know Boxsters but will, later, ask you where the engine is (happened to me twice).

      Be prepared for maintenance costs (including choosing a summer tire vs. an all season tire). There is a regular schedule that you should adhere to. If you take your car to a dealer for maintenance, a good one will remind you via the mail.

      If you do buy one, you WILL enjoy driving it. Putting the top down and cruising is like a mini vacation. The manual is more fun to drive. Auto-crossing the car is more fun than I can describe. If you are unfamiliar with auto-cross, look it up on Youtube. It will teach you the limits of your car and of your driving skill level.

      Notes: It’s rear wheel drive so avoid driving in snow, particularly in a hilly area. Make sure that you keep your battery charged if you don’t plan to drive the car for a while. On the older models, you will have difficulty getting to the battery to jump-start the car.

  36. I bought a new central lock control module with remote control for Porsche boxster 1998 model.I then used it to replace the old one which was faulty, but the car refused to come on although the ignition is working. Please your candid assistance is required.

  37. Hi guys, girl needs help – I bought a second hand porsche (1999 Boxter) a few weeks back but have trouble now as the car is driving rough, won”t go over 20km hr, and engine test tells me its running on 5 cylinders. I replaced the spark plugs as they were original, but the condition is still there. I am about to replace the Beru Coil in cylinder one, but wondered if anyone else can tell me what the problem might be? Cheers!

  38. Sounds like a bad spark plug to me. If there is no light showing up for the Air Mass Sensor, then I would change all six plugs with good ones.

  39. Author

    You could swap coils between cylinders to see if the miss follows the coil. If it’s not ignition, the. It is probably eith the mass air flow sensor or the EGR valve/canister.

  40. Thanks guys! I have already tried the spark plugs with no joy, but now just bought a new Beru coil, so will try that. The engine light comes on too – so hope thats normal for this issue.

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