Erratic idle + CE light

[tribe]

hi guys; its been a while.

My ,08 40K miles started to act-up in idle when warm. It goes down to about 800 and idles like an old diesel and fluctuates up to about 2000RPM or even more. Up and down all the time. It runs OK at highway speeds. The light turned on today; 3rd day after this thing started

I called-in for service but I have an appointment on the 30th. Meanwhile I'm driving to work this way to work.

I have it chipped from early miles but I drive like an old lady so this isn't related to abuse.

Any ideas?

Thank you!

[DoThisMyWay]

Sounds like the diaphragm in the PCV valve has a hole in it. Had the same symptoms and found this when I cracked open the old PCV.

http://kenjihosoda.com/car_images/IMG_0795.jpg

Do the RMPs hang at 2k in between shifts?

[tribe]

Thanks for fast reply! Indeed it hangs around 2K rpm and slowly goes down. Sometimes it even goes to 2.5k.

What do you think can cause the hole in the diaphragm? how many miles were you at when this happened?

[DoThisMyWay]

This issue came up around 85k miles. I've been APR'd since 10k though. The extra boost and a weak diaphragm material is the cause of the problem and it probably starts as a small hole that just keeps on tearing. The diaphragm expands and collapses constantly.

[tribe]

I'm still under warranty so will let them fix it but is this the part? http://www.ecstuning.com/Audi-B7_A4-Quattro-2.0T/Search/A4_Pcv/ES281180/ just to keep in mind for the future

[makav3li]

yep sounds like pcv.

[KraZ4Riding]

I'm still under warranty so will let them fix it but is this the part? http://www.ecstuning.com/Audi-B7_A4-Quattro-2.0T/Search/A4_Pcv/ES281180/ just to keep in mind for the future

Just a note on the part number, I just had mine replaced at the dealer a few weeks ago. The part number they used per the invoice was 06F-129-101-P. This 'P' version is certainly more substantial looking than the e or f one they replaced.

[DoThisMyWay]

Yes, that's the part but keep in mind it is VIN specific. Just watch out for the "up to Vin #6-165000" or "from Vin #6-165001".

[tribe]

Just a note on the part number, I just had mine replaced at the dealer a few weeks ago. The part number they used per the invoice was 06F-129-101-P. This 'P' version is certainly more substantial looking than the e or f one they replaced.

I just got my car back from the dealer and they changed that same part #06F-129-101-P. Does the APR chip blow this valve up sooner or is just a crappy part?