On my 99.5 Audi A4 1.8T Q I had a flashing cel and hooked it up to VAG and found out that cylinder #2 was misfiring. (16684 - Random/Multiple Cylinder Misfire Detected, P0300 - 35-00, 16686 Cylinder #2 Misfire - P0302 - 35-00)


I bought a new coil pack and a new set of NGK spark plugs. I cleared codes and swapped out coil pack for cylinder #2 and all spark plugs.

I started the car and noticed that the CEL was still flashing. So I took the coil pack from cylinder #3 and swap w/ cylinder #2 to check to see if the new coil pack was bad. Same error from vag, cylinder #2 misfiring. I checked the brand new plug in cylinder #2 and it looks like it is not firing as there is no residue.

Thought? I don't want to take it in, but am running out of options and want to get my car running. My only guess is that the plug wire for #2 cylinder is bad. Any other thoughts? The wires look a little complicated to swap out. Any write-ups on how to do it (even just to test if one of the wires is bad by swapping it out with another wire)?

 

I found a write-up on how to check the Power Output Stage module N122. I am going to do this as I suspect this could be the cause. Here is the link to the write-up that shows how to test this:

http://forums.audiworld.com/a4/msgs/1594531.phtml

If this is not the issue, then I will swap out the plug wires.

Hopes this helps someone else...

 

ICM (power output stage) is pretty much the last thing to replace to cure the misfire if you've done the plugs and coil packs.

 

did you gap the plug correctly?

 

I am curious to here how this ends. Keep us updated. Good Luck

 

was about to ask same thing, make sure the gaps on the plugs are in the 0.028 - 0.035 range

 

Sorry for the delay in response. I just got the part today and installed it. Flashing CEL was gone (need to reset CEL with VAG) and all cylinders are firing (immediate difference).

The good news is I know a lot more about the ignition system on my Audi and it has new NGK spark plugs as well as a new coil pack which did not fix the problem, but needed to be replaced as they were getting old.

Car runs great!!!!

 

Does your car have an ignition control module?

 

Yep. Problem was the Power Output Stage module N122. Replacing that fixed the problem. Also I did check the gapping on the spark plugs. From what I remember NGK's come pre-gapped, but I checked them anyway.