Car shuts off by itself after rough idle problem

[Jacques79]

http://www.youtube.com/watch?v=w-mHYcJsgvo

I have a 2000 Boxster S with 50 000 miles

CPO warranty until November 2009


Well I got stuck in the snow around 6pm tonight and had to a lot of reving in 1st gear followed by reving in reverse for like 30 mins straight...

I finally managed to get my car to move with the help of about 5 guys and then drove my car back to my garage and parked her safely with no fuss.

Now about 30 mins ago I wanted to start it up to make sure it's ok, and this happens:


Note: *On friday March 7th I took my car to the dealership and they replaced the Mass Airflow Sensor under my extended CPO warranty. Dealer said my car was perfect aside from the mass airflow sensor: no leaks no nothing*

The car idles at 500RPMs and then goes to 1000RPMs and then back to 500RPMs and then back to 1000RPMs. It does this for a good 20 seconds along with a very sorry-weak engine noise and all of a sudden the engine kind of shuts down calmly by itself.

All of this is happening without me doing anything: I'm not touching any pedals.

I started the car again and tried to get it moving a bit but it just died.

It's not a battery problem because my radio and lights work fine.

My car never did this before.

Please help, I know a lot of you are stuck at home because of the weather so chime in!

[tboyer]

Are you handy enough to work on your car? If yes, then remove the engine cover, disconnect the battery (make sure you have your radio security code) and finally MAF electrical connector (on the J tube behind the air filter box). Connect the battery and start the car, which will drop it into "limp home" mode. Observe whether the car runs better, if yes, it COULD be the MAF. From what I've learned, the MAF has nothing to do with rough or chasing idles. The most common reason for a rough and/or chasing idle is a vacuum leak somewhere. My rough and chasing idle was caused by a small slit in one of the rubber sleeves behind the throttle body. While you're at it, cleaning the throttle body is a good DIY which will help too. Many posts here and on other boards.

To remove the actual MAF you'll need a security Torx bit set available at Sears.

[Jacques79]

Car getting towed to the dealership in an hour, I should have an answer by noon today.

My bet is on the MAF sensor they replaced a few days ago. Maybe it wasn't done properly?

[tboyer]

Originally Posted by Jacques79

My bet is on the MAF sensor they replaced a few days ago. Maybe it wasn't done properly?

Hard to mess up a MAF sensor install, two screws and an electrical connection, I guess they could have installed it backwards or failed to properly seat the connector. Anyway, good luck and keep us updated.

[CJ_Boxster]

I've had a new Dealer installed MAF go bad about 3 weeks after it was installed so its not uncommon... I've experienced getting new BAD maf before so i know it happens from time to time.

[insite]

if it's not the MAF, see my post on this subject over on Rennlist. a vacuum leak is a likely culprit (oil separator bellows, oil fill tube, oil cap, etc.)

[Jacques79]

Verdict is in: Porsche says it's a defective throttle body. They ordered a new one for my car which should be installed in 1-2 days.

They tried installing another new MAF sensor but it didn't help at all.

Hopefully the new throttle body fixes the problem because I DON'T want to have to go back to Porsche next week....

And they refused to give me a loaner car even though my Boxster has been in repairs friday, today and will be tomorrow!

I called Porsche North America to complain but they told me : ''each dealer is independant''