'90 200 tqa running poorly

[Tony Hoffman]

Nick,

Sounds an awful lot to me like it's time to start checking for vacuum leaks.
Probably a big one somewhere, so it should be obvious.

Tony

On Mon, Jul 18, 2011 at 8:36 AM, Nick Lawrence <nick at beol.net> wrote:

> 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