Help... I have a 1995 F150 with 4.9L 300 EFI. It had recently started bucking when during acceleration... And now it won't start. I changed out the fuel filter just for grins, but no luck. If I crawl under it and have someone turn on the key, I can hear a click like a relay is being engaged and a faint buzz like the fuel pump is trying to work... but the sound is very faint. There is no pressure at the fuel relief valve even when I attempt to start it. I'm pretty sure it's the pump, but how can I test for a bad relay or whatever other problem I might have. I really need to get it fixed fast and can't afford to replace any parts that I don't need to replace. I hope someone can help.

Thanks