Starting problem on 5000tq

[dhuddles@gandalf.ca (David Huddleson)]

The festive season has allowed me some time to check over my Audi, as well
as allow it to display its desire for a $$$ sacrifice from me  :-(

I have a 1987 5000 turbo quattro sedan with 150,000 KM (about 93,000 miles).
The car starts well from cold, regardless of outdoor temperature, which
recently has been in the 15-30F range. Suddenly, starting on Saturday, the
car is now hard to start when it is warm... The car runs as if only 2 or 3
cylinders are firing. Within 20-30 seconds everything clears out and the
car runs fine.

I'm not sure what to check out. I considered the "warmup-regulator" and the
check valve of the fuel pump, but upon reflection the fuel pump valve would
also cause cold start problems...

Suggestions anyone? Is this a classic symptom of something I'm blatantly
missing....

Thanks,
David

PS. I've got a leaking plastic/aluminum radiator too, and am starting to
search locally for an all-metal replacement. Does anyone know if the radiator
for the 5000 quattro is the same as in the 5000 FWD (turbo and/or non-turbo)
from 1984-1989 5000 & 100/200. The original rad part # is 443 121 251 K

-- 
dhuddles@gandalf.ca   David J. Huddleson   Gandalf Canada Ltd., Nepean, Ontario
                      (613) 274-6500 Days  (613) 822-1315 Otherwise