SCSI

Yesterday I got bored and bought a compression tester from Harbor Freight. My other avant (B5 A4) is consuming oil and I wanted to see what's going on there. Then I tested the S6 and below are the results. Car is 2003 and has 85K miles.

Cyl: 1 2 3 4 5 6 7 8

Dry: 175 170 165 175 182 175 180 185

Wet: 190 205 200 195 205 210 210 200

Does that #3 cyl look suspicious? It occasionally causes rough idle and shows misfires when idling but no DTC. I already tried coilpack swap and new plugs. Stays with #3 no matter what I do. Next step I guess would be to clean the injectors...

willywacken

The idle misfiring issue is a problem showing up now and then with the 40V V8s. Mine does the same, except for cold, rainy wheather, then it ends to run absolutely smoothly. I already checked/changed spark plugs, coils, oil, cam timing adjustment (a known issue with Audi´s V-engines). My car is running on LPG, but the problem shows up on both fuel types.

Your compression values are okay, but I am not completely sure, whether the valve shaft gaskets wear over the years and cause problems I´m going to change mine in a few months, should reduce the oil consumption.

You should also check vacuum system for leaks, since this is also a common issue for idle problems (false air).

Greetings from Europe! :-)