4.3l chevy missing bad

i have a 93 chevy 1500 that the injectors keep cutting out and the truck is missing. ive gotten the codes and keep replacing sensors now its saying its the knock sensor. ive put a new fuel pump,cap, rotary button, ignition mod.,tps,plugs, wires. the code now is 43, any ideas or should i just keep changing sensors?also just replaced idle air control, no help .truck died in driveway and now will not start back up. will the knock sensor do that ???or could the idle air control i put on be a bad one???