I have a 6 speed manual 2001 a6 1.8T with 191,000 miles.
This past weekend, I was out driving, and when I was sitting at a red light, my car started to misfire. The check engine light came on and was steady. When I got the car in gear I could feel the misfire really bad until about 3000 RPM's when it would calm down. When I got the car at about 40MPH the CEL would start flashing. I pulled off the road after about a mile, and I noticed that I could smell a sulfur smell. I turned the engine off and started it back, and the car was back to normal.

The next day the car started doing the same thing minus the smell. The car would still misfire really bad up until about 3000-3500 RPM, and the CEL light flashed around 40-45MPH. I got it to auto zone and hooked it up to the computer they had. It said that there was a random misfire, and that one of the o2 sensors was not heating properly. I then noticed that the car was low on oil, since I had just had the oil changed.

Monday I got the car to a mechanic when he told me that I needed a valve cover gasket, ignition coil boot, and spark plugs. Well needless to say that didn't fix the problem. He called me back later and said that I had a "dead cylinder" and would be about 3500$ to repair. I got the car to a shop that specializes in audi, VW, mercedes, etc. The mechanic I spoke to said that he has never heard of that happening. He ran it through their computer and said that the 2nd CP is bad, a multiple misfire code, and 2 o2 sensors are bad, and a catalytic code.

I'm replacing the CP tomorrow, but is there any other idea as to what could be wrong. I was thinking maybe the MAF sensor, or the ignition control module.

 

than you

 

Replace the coil pack, clear the codes and see if they stay cleared. CPs are common failure items on the 1.8.

Good luck,

Bob

 

I replaced my CP today, now the car starts fine, and then starts misfiring after heating up.

 

1st Figure out which cylinder it is.

P030 (1-4 ) the last number of the DTC is the bad cylinder.

If it is misfiring after warm up. I would check the coolant level and if it has been low lately and you don't know where it's going. You could have a small leak in the head gasket that opens when heated. If you have a compressio tester nows the time to reacquaint yourself with it.

Also check to see if any oil is leaking into or on the CP. they are temperamental. I always pinch the female connectors closed when I re install the harness and apply di-electric grease to ensure a firm connection. I have had misfires from that alone and they started after warm-up. So check that.

Inspect the wires from the CP and the injector on back to make sure they are not shorting out or burning on something.

Check and test the injector. It's involved to do a volume test. But you can easily swap it with another cylinder and if the problem changes cylinders...


I have no idea what the hell kind of diagnosis a dead cylinder is and how the "F" you fix it with 3500 bucks.

You either have a specific problem or you go to another mechanic. You should be hearing that the Head gasket is blown or a valve is bent or the injector is messing up or something for him to chase around. He might as well have said you have sick car syndrome and he needs to get a sex change so it will be 3500...

 

thanks, I didn't have a clue what a dead cylinder is either. I have always driven chevy trucks until I got my A6, I thought it might be something specific to an audi or something.

As far as what the rest of what you said to check, the problem was in the 2nd cylinder. I replaced the CP, and now there is a volt spike in the 2nd coil. I'm thinking electrical now?

I did notice that before all this happened the car started to overheat a little, the AC started getting hot for about 30 seconds, and went away after that, but there isn't any coolant leaking at all. There was an oil leak, but that got fixed when I replaced the valve cover gasket.