1988 Chevy Truck cranks but does not start

Check fuses, and relay if its not one of these its your fuel pump. When you turn the key do you hear the pump working? It should hum for about 5 seconds and then stop. Iv'e had the same thing happen to me and I beat myself to death trying to avoid changing out a almost new fuel pump. I know there a pain in the sass but you can get weak or even bad new parts. Never let them run out of gas, this will burn them up quick, even one time can do it. You can try changing the fuel filter but Iv'e never seen a fuel filter on this model truck clog all the way up. Tapping the tank with a block of wood(if you can get to the metal part of the tank for the cover) may vibrate it enough to get it to work, again never hardly works and if it does its going to leave you stranded again.