Fuel pump on my 94 pick-up truck

The 350 engine on my 94 Silverado truck will crank but will not start. I checked the fuel pump fuse and replaced the fuel pump relay. I used a voltage tester on the fuse holder itself and there is no voltage reading on either wire to the fuel pump fuse. I checked all the other fuses in the fuse block located underneath the dash as well and they are OK. I poured gas down the throttle body and the engine does start and run for a brief period. The engine was working Ok, and when I turned it off, it would not start again. Two days prior to this, the check engine soon indicator light came on for a brief period(1 hr.) and then turned off.

Where/what is the problem and how do I correct it.

SIncerely,

Mark Gibbs