Per factory spec, they are to bereplaced at 60k miles. I didn't do mine until 80ish, and I waited too long.

You are correct as to what you'd expect to see w/ bad caps & rotors-really sounds like yours are new, though.

Change your O2 sensor (early cars have 1; later cars I believe have 2)...then, what I'd do is pop open the CAN box (where the battery is usually), remove the LH module for 10-15 minutes, then re-install. This will re-set your fuel injection, and you will go to full rich; your car will then begin to adapt itself, slowly.

Good luck!

__________________
"If God had meant for us to walk, why did he give us feet that fit car pedals?" Sir Sterling Moss

Michael
2014 E63S Estate
2006 SLK55
1995 E500
1986 Porsche 944 turbo