in post 1 he said he replaced the fuel pump,so i think he has eliminated the pump as the problem still exists.

I missed that part.
Also, when re reading, he said its fine when its cold, so the fuel pump is probably not the issue.

It sounds like the fuel is evaporating in the lines and causing a vapor lock type condition.

does the tank have a anti drainback valve,also known as a check valve?

fixx
 

if the pick up tube was cracked(at the threads towards the top of the tube) the engine would run fine with a full tank of fuel,then the engine would start acting up once the fuel level starts going down...

Does this sound familiar? if you do find a cracked pick up tube order 2 of them but the tube part made out of nylon..they wont crack..

proubably not your problem but worth a shot.have a mpi fuel injected motor and the sea water pump on the motor was weak,causing fuel to evaporate.let motor cool down would refire every time.not fimilar with your set up but the sea water pump is quick and easy to check.my engine didnt over heat or anything.just wouldnt restart hot