1993 GMC Sierra Intermittent Fuel Delivery System Problem

Is the engine 5.7L-- gasoline? When the problem occurs, when you first turn the key on, no crank, can you hear the pump run? If not, check voltage and ground at the pump connector, engine cranking. Voltage for the pump motor is gray wire. Black wire is ground. If you have good voltage and ground with no pump action, I suspect the pump.

A note, engine cranking, the pump gets battery voltage. Engine running, the pump gets alternator voltage, there is a difference. You need to use a fuel pressure gage, just to make sure about pressure. Some of the national brand auto stores used to loan out a fuel pressure gage if you don't have one. If you have TBI borrow a gage for TBI system.