mtnxtreme

My 09 Q7 V-6 is showing 2 codes, one for intermittent misfire, and the other shows misfire cylinder 6, so I pulled the old swap the coil packs trick. I swapped 5 to 6 and 6 to 5 and cleared the code. Car ran nice no miss, couple of days later, down on power, CEL comes back on and its showing # 6 misfire again? Any ideas, usually this rules out that #6 coil pack being good or bad. Could that plug be fouling ? Why then ould it run better when clearing the code ??

smith2010Q7

Could you post the Pcode? Need to look in the manual for troubleshooting process,

Thanks

mtnxtreme

PO300 and PO306

Dtomasi

A bad 02 sensor can cause p30x codes. Also check/clean your MAF aND also check for vacume leaks around the intake manifold. I would start there.

mtnxtreme

Any way to tell if the 02 is bad ?

smith2010Q7

thanks for the codes.
P0306 is your hard code which you are on the right track in swapping the coil packs, but you forgot to swap the plugs too, or replace them. I prefer to replace #6 plug and then clear codes and wait.
Next step if it does not swap then you have a injector problem/ fuel pressure problem.

below injector test.

Q7 Fuel Injectors, Checking P0306.pdf