Hi, i recently purchased an Audi 2001 A4 manual with 250k on the odometer and im in the process of doing some maintenance. I wanted to get rid of the code. The one being p0304. I a pretty DIY kind of guy and have most tools to do the job. The car was losing power around the 3rd /4rth gear and struggling or hesitating at that point until you let go of the gas a bit and let it go through. Sometimes the CEL would blink. Doing my research, this seemed to be a problem with the coilpacks and spark plugs. The recall was already done but i guess something failed again. I did the upgrade to hitachi style coilpacks and ngk iridium plugs. I cleared the CEL and the hesitation around the 3rd 4rth gear was also gone.

During cold starts though the engine really struggles/chokes and shakes, the CEL came back and at one point it was blinking again. It struggled before but not to this extent.
What else should I be looking at. Vacuum hoses I suppose, but any other ideas?
I appreciate your assistance.

 

I checked the codes again today, and there are 4 of them now p0301, p0302, p0303 and p0304. Did my situation just get worse or what.