Hi, I have been having some trouble with my A6. When I step on the throttle just a little bit, the car accelerates a lot. Also when I shift to N, the rpm bounces from 500-800. Then I shift to D and the rpm stabilizes, but I hear a sound like "frrfrrfrr" from the engine. I switch back to N and the rpm bounces from 500-800 again. I step on the throttle just enough for the rpm to reach 2000. Then the rpm drops slowly to 800 and stays stable. Sometimes when I slowing, just before I stop, I feel the car is about to shut off and I see the battery light turn on for a fragment of a second. And sometimes it does shut off. Today the car shut off in the middle of the traffic and I tried 4 times to start it. Finally it did start, but the rpm were 1100 on idle and the EPC light was on.