'90 200 tqa running poorly

[Nick Lawrence]

Vehicle is 1990 audi 200 tqa.
After a few stop and start errands Sunday the car wouldn't start. it would crank and occasionaly fire and quit. I swapped the fuel pump relay, then removed and jumpered the relay. I pulled off enough covers to hear the the fuel pump, it was humming.
After sitting, fiddling and cussing for about half an hour the car started but ran rough and really felt like missing.  
Made it home, replaced the spark plugs no change. 
However mash the pedal and it will rev and boost the normal 1.8-1.9, feels like normal power.  but back at idle and low speed still bucks and stumbles.

I swapped in another dist cap and wires.
It will stall when  the oil cap is loosened, but not when the dip stick is pulled. (I thought it used to)
I checked compression    130- 150 .
If fuel pressure was off could it still run boost and have adequate power?
If the oxygen sensor failed would the car run really bad?  In my million miles of Audi's i have never experienced any change good or bad when replacing oxygen sensors.
Anybody ever see an ignition coil fail in this manner?
 
Hoping for more ideas to check out.

Nick  central Ohio