steve - interesting note. But I still wonder if that has anything to do with the symptoms I am experiencing.
The idle has always been a touch rough. It seems that having replaced the chain increased, rather than decreased, the symptoms. And again, the pickup and the drive is perfect - no complaints there.
I know the timing cannot be adjusted - it's all computerized, so messing with the distributor won't help.
What I do wonder about is the following - what if the old chain was streched and had jumped a tooth on the crank (not the cams)? I would have kept the error because the new chain went in tooth by tooth, and the tighter chain would have knocked the timing off even more. Would one tooth on the crank have caused a catastrophic collision (if yes, I KNOW that's not the problem, because the engine performes well), or would I be having the exact symptoms I am having? I thought the crank was off by 1 degree or so, but I attributed that to simple machining slack.
I also wonder if a timing light could give me a clue as to what is going on...
The car has 104,000 miles. Secondary ignition all has about 5k miles. I hear no vacuum leaks, though I will investigate further...
1989 560 SEL (black/black)
2001 Audi TT Roadster (silver/grey)