Audi 5000CS Quattro Turbo - Stalling issue!

All,

I have a current stalling/starting problem with my '86 5000 TQ.

-Starting: Sometimes if I release the key before the motor starts
(generaly fires in 3-4 seconds of cranking), I have to wait ~5 min
before making another attempt. If I attempt to start before ~5 mins,
engine will maybe 'pop', but will simply crank (as if no fuel in the
system.) Happens mostly COLD, sometimes WARM.

-Stalling: Earlier this week, stalled out in an intersection (WARM
engine). Same as above, had to wait ~5 mins then restarted.


Any thoughts? Thanks!