Hi folks
I have searched the forum without success on this one. In the last couple of days, my 2001 tt coupe has suddenly started to idle roughly - it will hunt over different revs (800-2000) and occasionally stall at idle. No check engine lights are coming on. It has a brand new factory engine from last year, with about 12,000 miles on it. No mods other than a europipe stage 2 loud, which has been on all this year. I have it at my indy shop, and he has plugged it into his PIWIS (or whatever it is called), and it is showing no vacuum leaks, but airflow is up to 5x normal at idle. He changed the MAF's to test, but no change in the problem. Performance is not affected - it is revving fine, performance seems fine. I have tracked it 11 days, but all at green or yellow PCA level DE's.
Any theories?

 

when was the last plug change and have you checked coil packs?

 

The plugs are the originals, as are the coil packs. It is the sudden nature of the problem that puzzles me. As an update, my indy did discover that he was not able to get a response from the evaporation sensor (my words, paraphrasing what he told me) at the tank. I know I have read about some people having issues with the vent in the fuel tank causing drivability issues - I 'll keep you posted.

 

2001 with original plugs...in any case they need to be changed....you probably still have the berus in there...get the bosche.

 

Yes, but it is a new engine, so only 1 1/2 years - I agree it is getting there for plugs, but I don't think they would fail suddenly like this.

 

OK...I missed the engine part...Here are some other threads you might peruse

link 1
link 2

and you are sure you don't have any leaks or a bad DV?

 

Still sounds like a vacuum leak...