I know some of you folks have modified the knock sensor circuit with a resistor, or have relocated it. Can you achieve a similar effect by placing a very thin rubber washer under the sensor,or after 120K should I just get a new one?? Just trying to modify the "usual" Subie cold hesitation a little. Thanks all.

Not sure about the rubber washer. The sensor does at least need to be grounded by the bolt through the hole. I replaced mine with a resistor, but yes that means no knock protection.

I would recommend not messing with the knock sensor. I've tried a few things a while back, and none really improved things.

The knock sensor relies on vibrations coming up through the metal of the motor. It "listens" to the frequencies coming through the block to determint when a misfire/detonation is occurring. Insulating its mount would eliminate any vibrations, rendering it useless. If yours is working, don't bother it. If it's not, just replace it...just my advice.

~Erik~