The car (17k miles, '01TT, Stage IV) is hesitating pretty bad when starting from rest and also in 2nd gear. But only on low rpm - in high rpm, no problem at all. I did the spark plugs 500 miles ago, air filter is clean and I'm using (on and off) different kinds of octane boosters. Is there a timing adjustment on this car ? Thanks for the help. It's bad enough to cope with a LWFW and now this...

 

Never had the car hesitate. You might have a vaccuum leak but that generally is associated with a weird idle as well.

If there misfiring, then i would point towards your MAF. Also, if you noticed that this happened immediately after doing your plugs, then its most likely your plugs.

The standard gapping WILL NOT work for tuned cars which will cause it to misfire.

 

lots of different things can cause this, get a durametric and pull the codes.

and stop with the octane boosters!

 

mine was doing the same thing do a pressure test (i found 5 leaks)... fixed the leaks fixed my problem
tim

 

r34dy2walk: I changed the plugs and everything was fine. It started to hesitate just recently.
tvurt: I'll stop the boosters and see if it behaves.
And if it doesn't, I'll get the pressure test.
Thanks all.