1997 a4 2.8 12v

Got these codes a month ago and replaced the ICM. The codes went away and I got a new code for the bank 2 post cat o2 sensor. I believe thats due to a exhaust leak in the flex pipe which Im fixing this weekend. Today I checked the codes just for fun and got misfires on 1 and 3.

A week ago or so I got a misfire for just cyl 1. Now its 1 and 3. The car idled a little rough before I put the "new" icm in and it didnt change.

Something I should add is the ICM came off ebay from a store and was supposed to be a good part. There could be a chance that is a bad part, but I'm wondering if it couldnt be something else too.

 

Can't help you, but I like your avatar, lol.

 

Dumb question.... Do the V6s have coil on plug like the 1.8t? If so, switch number 1 with, lets say number 5, and 3 with 2. And see if the misfire moves.

 

No, two cylinders share a coil, but 1 and 3 don't share the same one.

 

I didn't think 2.8L engines had ICM's? I know the 2.7T does but thats a COP (coil over plug) design. Your power output stages should be built into the three coils.
I think you have a MAF problem.

 

The ICM is brown and on top of the airbox.

MAF? Maybe a cleaning? Brake cleaner?

The car stumbles a little off idle and hiccups every now and then when Im in high gear low rpms. Plugs are new.

 

I'm getting misfires in 1,2, and 3 now, randomly. It only happens when I'm on and off the gas, or going through gears. Drove 130 miles this weekend on the highway and no codes, but as soon as I get off and start changing gears, they come back.

How does the engine know its misfiring? The three cylinders are on the passenger side, which has a leaky flexpipe. I'm betting that it only leaks bad when I'm on and off the gas, causing the engine to rock and the leak to worsen. This throws a code for the rear o2 sensor. I wonder if it has anything to do with the misfires.......but are probably just two different problems.

Why all on one bank?

 

A random miss-fire could be from a bad exhaust leak. Do you have access to a VAG COM? You can log which/when cylinders are miss-firing using measuring data blocks, somewhere between data blocks 14-16 is the miss-fire counter. If its miss-firing at idle and not under load i would suspect an ignition problem. If it only happens under load, then its a mechanical problem.

 

this is JUST like my problem, cept i have a 1.8t

why does no one tech certified answer my threads !

good luck! ill let you know if i find anything on mine



TheBAT - we are only 55 miles away from each other, we should get together one weekend and have a misfire fix party! haha

 

How does the ecm know what cylinders are misfiring? How long does it take for the monitors to come back on after reset?

I'll be welding in the new flex peice today, so we'll see what happens afterwards.