I have a 87 Chevy 3/4 ton and the fuel pump will not turn on when turning the key. This had been a off and on issue for the last few months And we were able to pour a small amount of fuel in the throttle body and she would take off. We are trying to figure out our issue. So I found the fuel pump relay and put 12 volts to the pigtail and the pump did turn on so I believe that the fuel pump it's self is fine. We bought a new fuel pump relay today thinking maybe it was a bad relay and that did not do the trick. We also got a new fuel tank selector switch bc anytime someone bumped the switch with their knee it was always a pain to get it to start working again. What do I need to check next? Possibly the oil pressure sensor? Thanks for any info you all can give me