1996 chevy truck

i have a 1996 chevy 1500 with a 305 vortec but recently the fule pump quit powering on what could be causing this i have replaced the fule pump and sending unit and the problem isnt fixed

The most likely suspect is the fuel pump relay. Check the fuses also. Before replacing things it is good practice to verify that power is getting to them. Investment in a digital meter is recommened and you can get a good one for less than 50 dollars.