RE. Starting problems 5k

[rac@gpu.srv.ualberta.ca (Robert A. Cameron)]

I have had the same problem with every  audi I've driven(84 5k, 86 5KQ, and
89 200Q). The reason that it has difficulty starting when left for a
while(over 30 min, less than 4 hours) is that the check valve located on top
of the fuel pump is leaking. This leak allows all the fuel in the line to
drain back into the gas tank. In order to replace the valve your gas tank
must be almost empty becuse the fuel pump is in the tank. Replace this valve
and your  problem will be solved. Why it starts when its cold could have
something  to do with the cold start?

Rob