???fuel pump issues???

[v1500]

I replaced my fuel pump oh(1987gmcv1500,350tbi) 2 years ago very shortly after I tore the motor up it sat for 2 years I finally replaced the motor put a new batt. In turned on the switch and no fuel pump hum so I bypassed the relay and put in a toggle I drove the truck about 100 miles from home and it started running bad it blew an inline fuse I had a computer put on it it came back as a bad map sensor replaced it no help replaced coolant temp sensor throttle poss sensor then found a vac leak fixed it and it done fine for a few miles then ran bad again barley made it home could the fuel pump go bad just sitting?????