[V8] 1990 v8 intermittant running

[ian blondeau]

I have a 90 v8 quattro with 276k on the clock. Runs like a top. It had the failing crank sensor when I got it and wouldn't start hot so I replaced it. Put probably 3k miles of perfect running driving into it after that. I'm very in tune with my machines and noticed it cranking a little longer before it would fire. This might be unrelated but there have been several times where the engine has skipped a beat when I flip the headlights on. Odd. Last week I went to start it (warm) and it would not fire. No sputtering just an even crank. This lasted for 5-10 minutes and slapping the gas pedal seemed to have some sort of positive effect. When I initially notice the longer cranking, hitting the gas pedal usually fired it up. Odd. Now, a couple days ago while driving, I lost engine power. It stayed running down the highway if I feathered the throttle but if I gave it too much it would bog. Now it doesn't really want to start and run reliably at all. The CEL
 never came on. Last time I treid to start it I had to keep it running with the pedal and can't trust it to go anywhere. Anyone have ideas?