Hot Start Problem

I've been reading this newsgroup for years now, enjoying the helpful advice. I've gotten to the end of my rope with this particular problem and I'm hoping someone out there can help.
I have a 1995 GMC K2500 with the 5.7L TBI. The truck starts fine when its first started in the AM (cold engine). After the engine gets hot in the summer and I stop the engine, it will re-start right away with no problems.
However, if I let it sit for say 20-30 minutes, it will be hard to start.(1) I can crank it and it will not start. I continue to crank four or five times and it will begin to run, but will be very rough. AFter about 3-5 seconds after it does start, the engine will rev-up to 2000 RPM and smooth out and back down to regular idle. Once it starts, I can turn it off and it will start right up. When it's running rough, there is no black smoke that I can see, just a rough idle.
(1) If I let it sit for 45 minutes or longer, it will start right up with no problems.
I've done the following: -Replace plugs -New wires -New distributor -new primary ignition coil -new fuel pump -new rotor and distributor cap -replaced the injectors -replaced the fuel pressure regulator
Someone said something about a coil under the distributor rotor. Tried to get to that and replace it but couldn't get the bolts out. I was afraid I'd break them off.
Oh wise group, please offer me any help you can!
Dave Hill
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wrote:

Kinda sounds like vapor lock. There is a vallve in pump in tnak that is supposed to keep pressure in fuel line when engine is shut off but when it is hot and off for more than a few minutes, the pressure drops if valve is bad and then fuel turns to vapor from heat and forces more fuel to tank. It would be ruff until all the vapor/air is purged from lines. It would be the worst from 10 minutes or so to maybe 30 minutes after shutdown. ----------------- TheSnoMan.com
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