90 v8 fuel pump or relay or???

[barth at wilsongriak.com]

Signed on today so be gentle. I have a 90 V8 and here's the deal. Get 
up in the morning start the car, no problem. Work all day, start the 
car, no problem. Go to the store turn the car off for five minutes, 
PROBLEM!! The car will turn over but will not fire if the engine is 
warmed up. This winter it would restart in five to ten minutes but 
now that it's getting warmer we're talk'in 45min. Help me please. 
Fuel pump? Relay??

barth