Here's my other truck:
http://67-72chevytrucks.com/vboard/s...d.php?t=786383
At first I was going to just have one thread on both truck, but decided to have two separate threads.
I crawled under and found the knock sensor just above the oilpan in front of the starter. I pulled the wire and checked the sensor with an ohmmeter. 3.9k is what it measured, so that’s good. I put the wire back on and went to the top. I used this diagram to help locate the ESC Electronic Spark Control.
I removed the connector from the ESC and measured the Blue wire with the ohmmeter, it read .6Ω, not good. After fiddling about awhile, I went back under and pulled the connector off the knock sensor again and the wire measured open as it should. I put the wire back on the knock sensor and measured the end by the ESC and now it was at 3.9kΩ. I should mention that when I first pulled the connector off the knock sensor, I noticed the center part of the sensor was loose. So it looks like there is an intermittent short, probably the knock sensor.
Looking at the picture I took, I can see where the center part has a crack. I could probably put some high temp glue on it and be good for now. I’ll clear the codes and run it awhile and see if it throws any codes. So far it looks like a simple fix. I have read about problems directly and indirectly related to the knock sensor that can cause a code 43. I don’t want to throw parts at it, instead I’m trying to figure out how things work and determine the problem.