1988 light duty k2500 350 5.7l not getting fuel to throttle body

have an 88' k2500 5.7l 350 that is not getting fuel to the throttle body. at first i figured it was the fuel pump so i took the tank out and replaced that and also at the same time replaced the fuel filter, after replacing, cycled the key five times and it started up for about ten seconds and then sputtered and died. i was like ok lets check injector signal, so i did that and there's no problem there, next i checked the relay, it was good and even when i had the connector for the relay jumped and confirmed that the fuel pump was running it still will not run and is not getting fuel to the throttle body,so next i checked for crimped lines and no issues there. where do i go from here? im completely stumped.