I'm not sure where I heard this but hear goes.
Connect a timing light up as if you were going to check your timing. Shine the light on the pulley with the timing marks on it and then tap the knock sensor with somthing and observe the timing. If the timing retards when you tap the knock sensor then it is probably OK , if not replace it. The engine is of course running when doing this test.

Good luck,

Ron J.

THanks for the feedback. The cheapest I have found it was a Adavance Auto for 50 bucks new. If you could point me in the right dirction for the $25 one, that would be greeat. The timming light idea would be valid, if it wasnt already retarded to its maxium (when the code 1-4-3 is flashed, it retards timming all the way so theres no chance it can ping, thats why you get crap for performance...). FInally, the whole idea of trying the sensor in my friends car was to make sure it WAS the sensor, and not the wiring harness. My car is NOT pining, thats not the problem here, so i could careless if it is going to detect the pings on my friends engine, i was just wondering if the computer will pick it up and not give me that dumb idoit light.

Thanks again,
Blake