I got a 1988 f250 with the 302 5.0 small block and my problem starts when I first start it, it starts up will die out if I don't give it has right after then jumps up to about 1200 rpms and will sit there if I let it if I tap the gas it goes down and sits at 900 but if I hit the gas hard it sputters and doesn't jump on it like it should and when I drive it it'll bog down off the clutch in 1st and 2nd gear and after that it will be fine but if I drive around for say 30 min if I come to a stop and try to go again it'll big down and shut off and won't start until being let sit for about 10 to 15 min I have replaced my Ecu due to water damage cleared up for a day or 2 I've replaced my fuel pump, fuel filters, o2 sensor, throttle position sensor, map sensor, and have new plugs new wires and new distributor cap

 

Check for spark and fuel when the issue occurs. Since it is somewhat repeatable should be easy to figure out which one is missing.