1995 Jeep Cherokee My Jeep cranks but will only start when

Engine Mechanical problem
1995 Jeep Cherokee 4 cyl Four Wheel Drive Automatic

My husband replace the crankshaft positon sensor, the throttle position sensor, the idle air control valve and my vehicle has the same problem. It has a high idle and will not start unless we pump the gas pedal or hold the pedal to the floor. We do hear the fuel pump engage. What do you think we should replace next? It also dies sometimes when I stop at stop sign. Please help we are stumped.

Thanks.