Ok, so I have a 1995 K1500 5-speed, 4.3 V6. It has low power, particularly in 3rd and 4th gears. It is somewhat noticeable in 2nd gear from time to time. So far, I have replaced the following: fuel pump, fuel pressure regulator, dismantled and cleaned the TBI. Fuel filter, plugs, wires, cap, button, knock sensor, coolant temp sensor, distributor, cleaned all electrical contacts, checked TPS on a scope. It doesn't matter if it is in closed loop mode or not. It is MUCH more noticeable when running the A/C. I also notice the presence of gas on the inside of the air cleaner lid. I have replaced the MAP sensor, EGR valve, EGR solenoid, coil... I have no check engine light warnings. I am totally stumped on this one.