Why will car not stay started at all unless gas manually sprayed into carbuertor on 1991 Buick Century

Ive replaced fuel filter, fuel pump, fuel injectors, injector o-rings, fuel lines, throttle body kit, throttle position sensor, abc throttle body chip, mass air flow sensor, coil packs, spark plugs, spark wires, water pump, cadallidic converter, crankshaft sensor an quad driver module ( ECM component board )

Asked by for the 1991 Buick Century
2 answers
Injector pulse ok???.... Need to check with noid light!!
To answer your question; would require a systematic diagnosis, which which would certainly cost much less than what you have already spent, and give you a direct path to a solution!