1991 Chevy Caprice Car runs in park. Buckles, backfires, shut

Engine Performance problem
1991 Chevy Caprice V8 Two Wheel Drive Automatic 100xxx miles

I have a 91 caprice with a 5.0 305 motor. My problem is that my car starts up and runs in park. But once I take it out the drive way and press down on the gas, the car hesitates, buckles, backfires, shuts off. And sometimes has a pinging or knocking sound after it has stalled out. I changed a few things that I thought might have been the problem but no luck with any. I need help and dont know what to look for or check next.

a list of what I have changed and replaced.
spark plugs, wires, ignition coil, pickup coil, ignition module, fuel filter, rebuilt throttle body and injectors, pcv valve, coolant temp sensor, timing chain and gears, fuel pump and stainer, and throttle position sensor, switched out the pcm and made no differece. And there is no engine light on.

if you have any ideas what it might be ill be very thankful. Thanks for reading and your response.