I have a 96 Chevy 1500 3/4 ton with a 5.7 vortec eng will not start when cold, starts with starting fluid then runs fine until you turn it off and it gets cold again...no eng light on I've changed the fuel pressure reg and temp sensor...can someone please help.

 

Could be fuel pump,do you hear the pump run for about 2 seconds when you turn the key to the on position,whats the fuel pressure and how long will it hold it for?