1994 Blazer wont start

1994 Chevy Blazer will not start untill it sites for about 1hr. It has spark and the fuel pressure is reading around 55-61psi.:banghead: what im basicly saying is that once it sits for about 1hr. it runs for like 1min. or so and it stalls out.... i just got done replacing the engine and it ran fine for 5 days un til now and all the ignition and fuel pump and filter is new.....ty

1994 Chevy Blazer will not start untill it sites for about 1hr. It has spark and the fuel pressure is reading around 55-61psi.:banghead: what im basicly saying is that once it sits for about 1hr. it runs for like 1min. or so and it stalls out.... i just got done replacing the engine and it ran fine for 5 days un til now and all the ignition and fuel pump and filter is new.....ty

Watch fuel pressure when it stalls/quits.
Also watch for lose of spark to plugs.
Any check engine lights or codes?

the only code thar came up is for the wire under the dash being unpluged.....but i erased that code bc that was from timing it when we got this new engine in ill let u kno the other info then.....