The knock sensor is right next to the motor mount. If the mount is damaged or loose, it will rattle with a rough idle, and would cause knock retard.

The question is.... is the rough idle causing a rattle that causes knock retard, or is there knock retard that if being felt as a rough idle? Do you ever have erratic knock retard results when the engine is under load, possibly indicating a sensor or wiring problem? When the PCM detects a circuit problem with the KS, it starts throwing in a variable knock retard.

 

The only time I have noticed any knock retard is when my idle will mess around up and down when i come to a stop and it will chug for a second in this case my engine does shake a good deal.. I just talked to brian at pcmforless about the problem im having with my torque converter not staying locked on the highway.. he suggested i open my tb blades a little more to prevent that.. The idle is much better now since i put the GM TPS back on it though..

 

My 95 Z was doing the same thing, changed the tps sensor and problem solved.

 

Yeah it seems like the problem is pretty much gone with this other TPS on it.. The only time i have trouble is when i start it and go from park to reverse or something it kindof bogs down for a second..