I have been looking at this misfire / check engine issue for a few months. I have gone through plugs, coilpacks, fuel filter, pressure, vacuum leaks, and have come down to the flywheel. I was told by a some Audi service techs that did my timing belt service that a bad bearing on the flywheel can cause a misread on the position sensor for the flywheel. This looks like a expensive repair on this 04 A4 3.0 6 speed.

Is this common the 3.0ltr A4 car with less than a 100K on it?

Let me know, thanks

 

Never heard of that before. Is it actually misfiring, or does it just cause a fault code?

 

Do you have any codes pulled out??

 

Yes, PO 300, 301, 302, 303, 304 Random & multiple misfires, Multiple Cyl. misfires 1-3-2-4. The dealer replaced all the plugs and coils packs on Cyl. 2-3-5-6

I'm not heard of this issue but it maybe more common with 6 speed trans. and at 3 to 4K to due the work it's not cheep.

 

You don't wash your engine bay do you? Those packs will corrode and break away if they get wet. Try taking a couple out and see if they are wet. I would bet my money its still a coil pack issue, they down right suck on that motor.

 

Yes, I did several months ago and I think that is what caused the failure of the 4 coils.

 

So there you go that's your problem, when you clean your engine bay you have to be very careful, and not use the water hose...

 

The coil packs are the weak link for Audi, the 4 I replaced were bad the second I started the car and limped it months ago to the Audi dealer. Coil packs work or they don't there is little in-between. What I have is a misfire at idle, still runs well with average fuel milage. The flywheel bearing has been mentioned by a number of Audi repair tech's but it is a strange problem.

 

I beg to differ sir. A simple wet coil pack can arc against the cylinder head/valve cover causing a random misfire. On another note to debunk your statement, the 2.7T motors are NOTORIOUS for random multiple misfires caused from bad coil packs. It usually takes 100 miles of driving to trip the check engine light too.
I highly doubt you have a bad pilot bearing inside the flywheel.

 

Don't look too deep into it, your coilpacks are bad, change them and see for yourself...