I own a 2004 A6 3.01. It has approx 160K. I bought it used approx 4 years ago. No problems til now. The following lights are coming on intermittently; the EPC & ESP together, and the MIL with the other two, or alone. When the EPC & ESP come on, a small loss of power and no cruise control. A couple of times all three lights on and almost total loss of power. I've had it to the dealer twice and they said diagnostics indicated the Mass Air Flow Sensor needed replacing. This was done but problem still there. Does anybody have any suggestions. The shot in the dark repair approach is getting expensive.

 

Sorry to hear about the problems. I recommend the following.
1. Find a mechanic that know's Audi's. Maybe someone here can recommend a mechanic in your area.
2. Have you done the coil pack recall? If not, it may be triggering your MIL light.
3. MAF could have been an issue. I've been told that our cars have 4 of them. Yikes!

I'd get the Coil Pack recall done ASAP and see how it goes....