Car has new heated O2 sensor, new air filter, cleaned MAF sensor and Berdohl Protex Fuel System cleaner done purchased from Audi store. Car runs fine until I give it a good rev. Thinking I might need a catch can to replace the PCV system. Checked the spark plugs and Ignition coils, spark plugs were Aitolite double platinum and gapped around .40 give or take which I thought was a little excessive. My coils are scheduled to be replaced by Audi on Saturday since they were recalled. Really hoping to get to the bottom of this loss of power, rough idling and engine misfiring. Any advice would be much appreciated. Thanks in advance and Merry Christmas!

 

Did you ever find your fix? I'm having similar issue on my 97 a4 2.8q throwing p0304 with only symptom being shudder during accel.

 

I've done some research and got it down to a couple of issues. 1) Replacing the MAF sensor, tomorrow 2) Replacing the fuel filter, just because I'm sure it needs to be replaced and 3) Possibly installing a catch can on the PCV system. Mann fuel filter will be here Tuesday. Will update as I go

 

This might apply to you too: https://www.audiforums.com/forum/sho...d.php?t=148394

 

Replaced my fuel filter MANN and MAF sensor BOSCH. Started the car and problem was still there except now its only was only misfiring on cylinder two P0302 P0300 AND P0171. Thinking it may be a vacuum line since the engine, I believe, was swapped.

 

Likely a spark plug that's crapped up or loose. Change them - they're cheap for a 2.8. Get all new ones, gap them at .040" I believe for the 12v engine, and see if it goes away. I had the same issue on my 30v.

To the OP, your plug gaps are too wide - whether it's a 30v V6 or a 1.8T, you need a .032" gap for a stock engine, and .028" if you're chipped.

 

I did change plugs , with oe ngk's . Did not take care of problem. Although, did see a marked increase in power. Ran 1.5 cans of seafoam through fuel and shudder disappeared , for now , still throwing p0304 though... looked into replacing ignition power output stage module but 250$$ is a bit much for a maybe .. anyone in Rockwall Tx area have vag comm?