Maybe someone else is having this same problem out there. This is the third time code 43 has set and it always is an open knock sensor. I have followed the service manual and checked the wire to the ecm and it is fine. When I checked the sensor itself it was an open circuit both times. This is in a 396 stroker with forged pistons and at startup there is fairly loud piston slap. Both times the code was set was when I went full throttle from a slow roll. Is there any way the noise of the pistons could be breaking whatever is in the knock sensor? Thanks for any help.

 

Are you sure you have the correct knock sensor? 94 OBD-I is a 4,500ohm sensor. 96/97 OBD-II is a 100Kohm sensor. Are you sure you are not over-tightening them?

The sensor is actually a piezo (crystal) microphone.

 

Change the knock sensor. I had the same problem, it was a bad sensor. By the way self diagnostic tests on sensors are worthless alot of the time, at least that is my experience.