97 Chevy k1500 runs for about a half hour then dies and won’t start

My 97 Chevy k1500 5.7l v8 starts up fine
and runs great at first. Then after about a
half hour it starts to sputter and then dies
and won’t start. There is fuel getting to it
and there is spark at plugs but still won’t
start. I have replaced ignition modulator,
ignition coil, distributor cap and rotor, map
sensor, throttle position sensor, crank shaft
position sensor and vehicle speed sensor.
Still have same issue. Any ideas?