In the past 6 months the truck went from running fine to dead in the water. It progressed gradually from running rough to stalling while driving to sporadic starting to not starting at all. I replaced the cap, rotor, spark plugs, checked for spark and put a meter on it to make sure it had good spark. I tried spraying starting fluid in the intake to no avail. Pulled the bed of the truck off to try changing the fuel pump and for the heck of it tried running the truck while the pump was in a can of gas. For whatever reason we tried starting the truck with the pump out of the gas and it started, when we placed the fuel pump back in the gas the engine wanted to die. I replaced the fuel pressure regulator but that didn't help. There is a small hole in what I believe is a breather line coming from the fuel pump assembly but not sure if that would have an effect. Tried unplugging one of the injectors at a time and no help. Any advice would be greatly appreciated.