I have a 2001 A6 with the 2.7T and tiptronic. Intermittently when I step on the gas, it seems like the turbos back up, and I have to let up on the gas and then go again to get any engine response. I have added the APR chip and new diverter valves, but get the same problem. I have heard this may be related to the brake sensor. Does anybody else have the same problem, or have found a work around?

 

how many miles are on your car, maybe a bad cat, all that boost and no where for it to go ?

 

can you VAG the car? my guess is that you have a Charge Pressure problem. Could be a boost leak if its negative deviation. Or possibly a N75 valve problem (common ground wire problems)

Its not related to the brake sensor so much as it could be the brake booster (which is related to the car's vacuum system.) A leak there could cause hesitation.