1994 Chevy S-10 Starts fine cold, Won't start after warmed

1994 Chevy S-10 6 cyl Four Wheel Drive Automatic

Hello, My truck in the morning starts just fine. I can hear the fuel pump hummm when I turn the key on. I would let it run for a while and turn it off. When trying to restart it, the fuel pump will not engage(no hummm) but motor will turn over but won't start unless I let it sit for a few hours to cool down. I have changed the spark plugs recently and wired and fuel filter. Fuel pump relay or ignition module?