85 PU 22re: Check engine light comes on at 2k rpm. Pulled code 12... knock sensor needs to be replaced. My question is, does the sensor thread through the block into the oil jacket? or does it thread only part way into the block? I am wondering if I need to drain my oil first to replace it.

Thanks

 

No need to drain the oil. I would first pull the sensor and make sure the threads are nice and clean on both the sensor and the block. I had the same symptoms, took a battery terminal brush to all the threads re-installed and it hasn't come back.