2002 Audi TT Question No Throttle Control

The first thing I would do is to check and make sure that all of the fuses are okay. Its suprising to see how many electrical systems are ran off of one fuse.
Unfortunately this is a hard problem to diagnose without a scan tool with the data stream display where you can monitor all of the inputs and out puts of the system. What I can tell you however is that The accelerator pedal position (driver's intention) is a main input unit for the ECM and could POSSIBLY be the problem. Almost everything else in the "E-Gas" System is ran off of what the computer tells it to do.
Let me know if you have any more information or questions.

Thank you for the quick reply. D you know of anyway that I may troubleshoot to try and narrow it down. I did not find any blown fuses. This problem occured about a month after an alternator change if that may b related?

I can't say if the alternator has a hand in this problem or not but since it was put in fairly recent it would be a good idea to have it looked at again and it should still be under warranty. If its a remanufactured alternator sometimes they will go bad in a short time period and do some weird things to your electrical system especially if the voltage output is below the threshold or if a diode is burned up.

Another thing you can do is call around to some of your local autoparts stores like checker or autozone and they can pull up your diagnostic trouble codes (DTC's) for free and that can narrow things down quite a bit. Sometimes they can even check alternators for free as well.

However when you do call make sure to ask if they can pull up the codes on an audi, so you don't waste your time.

Well those are two great places to start.
And if you have acess to a nice DVOM w/high Impedance I can try and walk you though some more test. I'll be checking back. Good luck.