Also, don't get a code reader locally. Get one of the special VW ones that well actually read your codes. Heres a good one:

http://cgi.ebay.com/ebaymotors/VW-AU...motiveQ5fTools

 

how many miles on your TT?

what gear are you in when this happens? are you on the throttle, cruising, accelerating?

 

It's not an automatic. The guy at Autozone said there should be a fault code in the computer memory, but I called the dealer who just tried to diagnose it and they said there wasn't one.

Sigh. Meanwhile I keep losing power when pulling out into intersections. Fun fun! It only happens when I am stepping on the gas, btw.

There's a local shop the autozone guy said will read "precodes," which occur when there's an intermittent fault, so tomorrow I am calling them with crossed fingers and hoping they can see something in the memory bank that Penske Audi missed.

 

Some codes trigger a check engine light and some do not ("pre-codes"). All of these code are stored in the cars ecu until they are cleared manually or after (I think) 100 engine starts without tripping the code again. If the check engine light was on, the code is there, absolutly no question.
I would suspect the mechanic cleared the codes when they got the car then test drove it and the car drove fine and did not set off any codes. He would have scanned the codes directly after the car had issues to reduce un-needed repairs on other unrelated codes.

You need to try to read the codes before anything can really be concluded. Its starting to sound more like an electrial issue now. I know of a guy who has a simular problem with his vw. His is related to the main engine wireing harness, but he can't figure it out and is too broke to take it in.

 

^^^ Yes after reading your OP again, it's the same problem my buddy has on his vw golf (same platform as the tt). The problem is that his is the 2.0L engine, so it's going to be a bit different. It's the wiring harness under the plastic grill thing right by the windsheld wipers. On his engine it goes from the center of the windsheild then more towards the pass side of the car and after that the wires run more under the engine and you can't really see them.

The car would run very poorly or not even start then he would shake the wire harness around and it would run fine. VW/Audi are notorious for wire connector to become loose, as in the plastic parts fit fine; however, the metal parts that touch and complete the circuit do not touch.

 

^wiring harness issues arise most typically when the harnesses have been screwed with, although this is not always the case.

I have dealt with the same issue (tracked it all the way down to the ECU pinouts). It's a bitch, but you should have a mechanic or mechanically-savvy person check the engine harness.

 

Got a source for ECU pin outs? That could be handy...

 

for a subie...

 

What's an ECU pinout?

Got about 85k on the car. Happens when putting around or on the freeway, no difference. Going in tomorrow to a local shop that has agreed to read for precodes. Will report.