man...i posted a while ago about my a4 1.8 popin...its still going on...i no its misfiring but why...spark plugs...head gaskets...air/furl pressure...(sounds liek rx7 on crack)...misfireing only occurs when full gass is applied.

 

Have you checked the plugs & wires? Try visibly checking the wires at night to see if you get any sparks to the engine.

I had a car that would misfire and stumble only at high throttle...turned out to be a loose connection. I thought for sure it was something else becuase it didn't misfire at all the time.

 

could also be a sign of the o2 sensor on it's way out, or even a boost leak. Have you done any mods lately?