N_Jay

My 2000 2.8 A6 just started having a problem with very occasional random misses.
Typically one or two in a 30 minute drive.
No check engine light, no stored codes from a standard ODB/CAN reader.
Never more than one at a time.

138,000 miles

I was figuring after a day or so, a CEL or code would show up and give me a hint where to look, but so far no luck.
Trying a bottle of fuel injector cleaner, in case it is just a bad tank of gas.

Anything common enough to try?

Plugs may be old (100K miles, not sure) but my experience is that bad plugs make much less intermittent misses. Thoughts?

(Cross posted from C5 forum for best answers)

Prospeeder

Best way would probably be to have vagcom and watch the misfire moniter and when it misses watch and see which cylinder logs the miss. Its probably something like the ignition coil, one of the 3 packs are no good, they are replaced as an assembly though.

N_Jay

The trick will be catching a miss, as they are very infrequent.

Prospeeder

It will stay logged as however many times that cylinder missed on the misfire moniter measure blocks.. So should be easy to spot. So if it misfired 4 times on cylinder #1. then it will say "cylinder #1 --- 4" saying it misfired 4 times. It goes back to 0 i think in a minute or 2. it wont log a fault code unless its misses many more times before counting back to 0.

N_Jay

That means having the laptop in my son's car.
Not good for to and from work.

Maybe something I can play with on a weekend.

Thinking it is going to get a new set of plugs and a few crossed fingers.