I have a 1991 chevy K1500 5.7 truck. The truck is hard to start and when it does start it will not idle.

This truck is hard to start and will not idle. I have replaced the tps, map sensor and coolant temp sensor. I have rebuilt the tbi new intake gasket, checked fuel pressure replaced fuel filter. Checked plugs wires and distributor. I can get the truck to run for a few minutes if i feather the throttle and it warms up if the map sensor vacuum line to the tbi is unhooked and the coolant temp sensor is unplugged. The minute either of these are hooked back up the truck dies.