got a mechanical question for you, got a 94 chevy k1500 with a 5.7 v8 with throttle body injection, boggs down at stops and when accelerating basically anytime there is a load on the engine, fine when in park or neutral, replaced spark plugs, wires, coil, air and fuel filter, oil change, and idle air control valve. still does it not as bad but still does it, there is no cat to get clogged but the muffler does have a hole in it
you might want to check your EGR valve operation. it works on two things at once, vacuum and exhaust backpressure. The vacuum part may be working correctly but the backpressure may be opening up the EGR because the spring is weak. Try driving it with the EGR vacuum line off and plugged. If it seems to be gone, replace the EGR valve. If you do need an EGR valve get one from the dealer or an AC Delco one. I have found that some aftermarket valves don't work correctly for these 90's vehicles.