Rather than go off topic in the Borg warner thread, I'll mention it here.
The stock knock sensors aren't the best design, and being old there's no way I would rely on them.
Look into changing them out for some Bosch sensors off something heaps newer! The stock thread is a 3/8bsp (weird hey) the so you can get a plug and drill and tap that m8 or something strange cos you are an American , and bolt the new sensor on.