One problem related to automatic transmission has been reported for the 1999 Audi A6. The most recently reported issues are listed below.
My car was accelerating without the gas pedal being depressed. I was fighting to stop the car with the brake but failed to do so as the car was accelarating at high speeds on a major highway. I had got the car down from 50mph to 15 mph. At this point turned on my hazardous lights and pulled over to the shoulder. At 15 mph I safely shut my car off as I was unable to completely stop. After 30 seconds, I turn my car back on and see that the car is hittig redline of 7000 rpms in park mode. I shut my car down once more and wait another minute. I start the car and the car is back to normal. I am being told by many people in my car's internet forum that this has been happening to many people and it is a faulty throttle pedal. The pedal has a heating element that has failed due to the recent extremly cold weather.