my 89 RS 305 is producing a code 43. i replaced the knock sensor, it didnt appear to be working when i tested it, but it could be that my inexpensive volt meter isnt sensitive enough to pick up the voltage when i taped the block. now im thinking that the electronic spark control could be at fault. i did test that, and i get voltage at the wire being fed from the key switch, the wire going to the ecm, and the wire going to the knock sensor. my stepfather has an old rotted out s10 blazer with a 4.3L Z code engine(junk truck). is the electronic spark control the same? i know its a v6, are they calibrated differently or something? i dont really feel like spending 70 bucks on a part like that. i was thinking of looking the in junk yard for one as well.

 

What are some of your readings from the wires at the ecm and at the ESC?