I have a 98 A4 Avant Quattro 2.8.
After filling with gas we get a pronounced misfire on 2 and 5. not right away but after 30-40 miles. Check engine light flashing, stop wait a few minutes and car will run normally with check engine light on, but not flashing.
Mechanic has checked everything, but cannot find reason for misfire. He has driven it about 50 miles and cannot get it to misfire. Any ideas?
The only variable I can be sure of is he always gets the car cold and doesn't know about the filling with gas part. Either did I until Saturday


Thanks,
Bruce

 

What exactly has he checked - what do you mean by "everything"?

 

When we first got our B5/A4 we got an incredible deal because it was doing the same thing and 2 mechs told the previous owner it would be around 2k to fix - though they were hazy on what they would be fixing for 2k... anyway, we took it to a mech at a high end shop and he didn't know what was wrong.. then we found a cheap mech of craigslist - for 30 bucks in labor and in less than 20 mins he said it was the coil pack.

We picked one up, put it in and it fixed the misfires... total cost: less than $100 - and the previous owner dropped over 2k off his already reasonable asking price...

My point is, I'd start there. It's a pain to diagnosis because it is intermittent. Further, since ours has a fair bit of mods to it, including supercharger, which pushes the stock coil pack into the hood insulation, we have had to replace the coil every few months. Though, I just found the ICM delete/ coil convert. kit from someone and will be putting that in next week.. so, no more coil issues/ misfires!