Cold Start Stumble

[Rich Letsinger]

Howdy. I'm a new poster to this list and have an urquattro with a 3B in it.
I'm running factory engine management with everything except the after-run
pump hooked up as it would be in a 200.  On cold startup the car stumbles to
life, barely turning any RPMs at all until I blip the throttle.  Once the
RPMs have exceeded 1K or so she runs perfectly, doing the normal warm-up
cycle stuff and then settling down to the 850 RPM idle.  All other bahavior
is normal include warm restart.

The bypass is new and I've just finished weeding out any vacuum leaks.  I
cleaned the ISV with carb cleaner and it seems to work correctly in every
situation except cold start.  It never used to have this problem, started a
few months ago and has been getting gradually worse.  Are there any other
things to check?

Thanks,
Rich