2002 A4 Turbo 1.8L

I have had this car for about three years, and last month it started having issues with acceleration (shakes if you press on the gas), idling really rough, and CEL flashing.

I have the Ross Tech VCDS, did a scan and found faults on 3 of 4 cylinders, with the 4th being intermittent. I replaced all four ignition coils and spark plugs, which fixed the problem. The car was purring! Left for a road trip, over 1000km, and the week after I come back, the car started having the same problems.

Scanned the car again, and it came up with a fault in cylinder 3. I thought maybe the ignition coil was a dud, so I switch coils 2 & 3, and scanned the car. Sure enough the fault moved to cylinder 2. I replaced the coil again, and again, the car was running smooth.

After another 150km... same problem... same cylinder.

This time I replaced the coil and the plug in case it was a bad plug, and made it back home (20km) without problems. The next morning however, the car started having a fit again.

Any ideas on what could be causing only coil #3 to fail?

 

do u see any oil one the sparkplug or at the end of the coil. Might be a gasket letting oil ruin your spark?? are u sure u are getting the revised coilpacks cuz audi had a recall on those bad boys!

 

The first time, when I changed all four coils and plugs, the plugs were completely coated in oil! I don't think they were ever changed by the previous owner, and I bought it at 9 years old...!
There was a trace of oil on the tip of the coil when I changed it a second time, but the plugs have been clean ever since. This is the fourth time I've changed the coils, so I don't think I'm getting the old coils each time...but not certain.

As an update: I changed out the coil in cylinder 3 again, but it didn't help. Car was still running rough, no boost, etc.
I got the car home, and scanned it again. This time it found:

4 Faults Found:
17887 - Brake Boost Vacuum System
- P1479 - 008 - Mechanical Failure
16684 - Random/Multiple Cylinder Misfire Detected
- P0300 - 001 - - MIL ON
16687 - Cylinder 3
- P0303 - 001 - Misfire Detected - Intermittent
16688 - Cylinder 4
- P0304 - 001 - Misfire Detected - MIL ON

So it seems something is causing all the cylinders to slowly die, not just #3.
Could it be ICM?

 

AMB motors do not have ICM's only AEB motors.

It could be that you have a short in your wiring harness. I would inspect cylinder 3's connector and follow the wires back through the harness. With the heat cycles these motors go through and the harness being so close to the heat source it is very possible to melt the wire insulation or cause it to crack.

Jason

 

u know i would check your vac lines and to be more specfic suction jet pump also. With that brake booster code you might have a really bad vac leak. My sjp split apart just the other day and caused a multiple cylinder misfire. . .

 

Paul, you were right with the first suggestion. I was getting my coils from Napa, and turns out they were giving me Chinese knock offs.

Finally switch them for OEM coils, and they're holding up well!


Thanks for you suggestions.

 

thats why we are all here! All you need is ask!