Conversation Between Bergerson and groverg

HI I have a 94 F 250 7.5 engine had the waterpump replaced because it was leaking, now it is overheating. This is what it does,,I start out in the morning it is all good. when the truck warms up and I get at the posted speed it starts to overheat. When at a stoplight the truck is overheating and when I take off it cools down somewhat. When it is overheating the idle is higher. When I stop and put it in park, with the truck overheating when I bring the idle up it cools down. As soon as I let off the gas it heats back up. I have already replaced the fan clutch(which I did not need) I am pretty sure I am going to replace the rad, hoses and thermostat and belts. I will flush the engine and blow out the heater core. Help. I do not want to spend to much money. What is the most likely thing I should do next.