Anyone help or had the problem before I have an audi a3 2002 that has had a stage 1 map and an exhaust system when driving at high revs the epc light comes on and puts it into a sort of limp mode (looses power) and know why this is doing this and how to resolve it ?

 

Anytime the ECM sees the slightest implausible signal from the electronic throttle body or throttle pedal it will go into limp mode where you have little or no throttle control. Sometimes I think it's a little too sensitive. You may have a problem unrelated to the modifications. I can remember replacing the wire terminals and hardshell connector at the throttle body many times for EPC faults (Electronic Power Control). Believe it was a TSB about it. All it takes is a split second bad connection (even too high a resistance in the circuit) and "limp mode". This was on the 2.0T. Rarely was it an actual fault in the throttle body itself. In a couple cases, had to run an entirely new circuit from the ECM to the ETB.
As I said, very touchy system for the slightest little fault. Then again, Audi never had the Toyota problem did they???
There are other things that will cause the EPC to go into failure mode (generally accompanied by the SES light) but I can't recall them at the moment. Haven't been an Audi tech for over a year and some of the memory files in my brain are fragmented.

 

So what could be the actual problem and how can I resolve it as it is very annoying, I have been told to put a bolt down coil pack from someone as it worked for them.

 

do you get a check engine light?
does it happen after/during rain and goes away after a day or so?