I have a 01 blazer 4.3 that starts great the first time but will not start again for at least an hour or two. Engine cranks and has spark. I checked for gas at the valve on the fuel line and there was pressure but do not have a gauge to put on it.
This started after replacing the motor. Is there anything I missed maybe? The motor runs great when it starts.
Any help would be appreciated

 

how long will it run? does it die or do you shut it off?

I just had to replace my fuel pump, constantly dying and shutting off on me.

 

Test fuel pressure when you are experiencing the no-start.

 

It stays running and there are no problems until you shut it off. then it just cranks and cranks and won't start

 

my guess is fuel pump or fuel relay.

 

So... Test the pressure. It is a diagnostic starting point. The results of which can help you determine the proper direction to go in.

 

I don't know exactly how I fixed it but it works great now. I started it and let it run for about 30 minutes and now it runs like a top and starts whenever you need it to. I'm thinking maybe the computer had to relearn the new motor.