I have a 1991 Chevy k2500 with a 5.7 tbi. It just happened the other day where the truck just shut off like I turned the key off. Then finally got it running and it ran fine for a couple days and then happened again. Had it towed home and today put a new fuel pump and fuel pump relay and got it to start 2 times but then died and now won't start again. Does anyone have any idea where to go next?