Noir Taylor

okay I will try and explain best I can; first It started with a spark knock. I came to that conclusion cause it only knocks while driving past 50 mph.
So, I changed:
fuel filter
knock sensor
flushed combustion chamber
changed egr valve
map sensor
idle control valve
throttle position sensor
spark plugs
spark plug wires
O2 sensor
vacumm hoses

I still get spark knock, but at this moment my concern is the shut off. It turns over and starts fine and idles great, with van in park very slight pressure on the gas pedal van stalls and wants to cut off. With van in drive and foot on the brake and very slight pressure on gas pedal van cuts off. If I press full on the pedal in drive and foot on the brake van runs and I still get spark knock if I push on the pedal farther down.

So, the only thing I can think of being the problem is fuel pump or fuel pressure regulator. I'm not in the mood for changing that **** in less I could truly be the problem and I'm forced too.

I am getting no trouble codes with the tester I have OBD1 Bosch scanner.

Any insight on the matter will be helpful
thanks!