I have been trying to fix a check engine problem. I have been working on this problem for a few months. I have codes P0301 P0303 P0302 P0304 multiple miss fires on Cyl 1-3-2-4. I've been working with an Audi mechanic and we have looked at CO sensors, vacuum leaks, smoke testing, ECU, Hot wire, fuel pressure, fuel rate, plugs and replaced 4 coil packs and spark plugs.

Is their anything I missed, any Audi geniuses that have some more ideas?

Thanks

 

Have your mechanic check the fuel injectors. Ohm them out and use a noid light to make sure they are firing.

 

^^^ i was about to day that...
also, question to you OP, did anyone install any new software on your car? or did anyone raise your idle with VagCom?