1988 Mazda 626 check engine light/engine stalls

Engine Mechanical problem
1988 Mazda 626 4 cyl Front Wheel Drive Manual

what causes the check engine light to come on and the engine to stall only at normal operating temperature. Vehicle has new plugs(gapped properly), wires, distributorcap and rotor, fuel pump and filter, coil and air filter. Vehicle runs fine until it gets hot then the check engine light comes on or idles erratic then shuts off or it will shut off when the brakes are depressed. Vehicle will start up immediately after shutting off. No remedy disconnecting the brake booster vacumn line either. Suggestions?