Excellr-A8

I am having a problem with my '98 A8 when it gets cold out. The problem started three years ago when it was at least -10 it would have a miss at idle and then the engine light would come on. It only misses for a couple of minutes then it runs fine. Last year it started missing when it was below about 15 degrees out and now this year it looks like it is starting to do it when it is around the mid 20 degree range.

I pulled the codes and they are listed below:

5 Faults Found:
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-00 - -
16692 - Cylinder 8 Misfire Detected
P0308 - 35-00 - -
16687 - Cylinder 3 Misfire Detected
P0303 - 35-00 - -
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-10 - - - Intermittent
16692 - Cylinder 8 Misfire Detected
P0308 - 35-10 - - - Intermittent

Last year I moved the cylinder eight coil and switched the two modules to see if it would move the problem to a different cylinder or cylinder bank. The problem didn't move so I am not sure what to try next. It is generally the #8 cylinder with #3 cylinder sometimes.

I wondered if anyone else ever experience this type of problem or if anyone could think of anything that would cause this temperature related misfiring problem.

Jeff B.

icsamerica

Get a Ohm meter, disconnect the fuel injector wires, read the resistance of the fuel injector coils. they all should be close. I'm guessing one or more will be way off. Do this when the engine is cold and the misfile is most likely to happen.

tozoM8

I fixed the leak and no more problem.

Excellr-A8

Re: Where was the vacuum leak?

tozoM8

On my wife's 94' 100 I have misfire due to a vacuum leak. I need to find that one. I am just waiting for the weather to get really cold, than I will fix it.