Like it says... I have a 99 1.8T , the previous owner install a test pipe on the car, and he say's that is why the check engine is on.. sometime when you have a full throtle or half throtle the engine hassitates just a lil... I need help, I'm little new to the audi familiy but not old for tunning and playing w/ cars... so help me out guy!!!

 

go here
https://www.audiforums.com/forum/search.php
and type in
'o2 sensor' and 'anti fouler'

 

With a non-fouler installed the test pipe can periodically cause a CEL, but NOT hesitation.

 

ok, guys, the previous owner install a "spacer" on the 2nd O2 sensor, and still have a CEL.. and hasitates... Also I found a one of the Vacumm lines of the intake manifold not very tight and secure, and that is the same line he pulled the boost gage reading will that cause it to hasitate??? thanks for the info so far..

 

you need to get the code for the CEL scanned and post it here.

 

ok, cool, I'll take it to Advance and have it scan... I see where I lot of people are talking about a VAG-COM.. where can I get that and how much???