Ok, this problem is interesting.

I have a 1998 A4 2.8 with Quattro and Tiptronic. The car has a history of electrical arc problems with the spark plug wires.

The specific problem: When the car is started, it does just fine. The engine turns over great and rests at around 800rpm. However, once it is put into reverse or drive it remains at ~800 (even when the accelerator is pushed) for about 10 seconds. It acts sluggish for those 10 seconds then as if by some miracle, it runs perfectly fine again and the rpms rise up to their normal driving range based upon how far I depress the accelerator. It only happens after turning the car off and letting it sit for a while (1hr or more).

Hooking up a OBD-II shows P0303 and P0306, piston misfire on pistons 3 and 6.

Any sort of insight into this problem or what is causing it would be greatly appreciated.