Why does our 93 Ford Escort shut off in the hot weather? on 1993 Ford Escort

Our 1993 ford escort keeps shutting off when the temp outside is over 80 degrees, runs good under 70 degrees outside. We've changed the fuel pump, the distributer cap, water pump, the fan, the radiator, the spark plugs, air filter, fuel filter, battery, all the fuses. Still have no Idea why the car sputters when we slow down or accelerate, and shuts off while were on the road. what

Asked by for the 1993 Ford Escort
Possible faulty idle air control (circuit). NO check engine light , right?