1990 Chevrolet Truck • 160,000 miles

My truck has a 5.7 v8 with a 4sp auto trans the truck stalls once it is warmed up and comes to an idle it does this a lot not everytime I drive it but a lot I have replaced the throttle position sensor the air control valve on the tbi cap rotor wires coil spark plugs fuel filter I checked the egr valve to make sure its working but I still cant figure it out any help would be appreciated thank u for your time
October 10, 2011.

Check for vacuum leaks and make sure the IAC is getting power.