I found out today that if you run over something in the road, i.e a piece of plywood like I did today, your knock sensor will pick it up. Mine registered a whopping 139, it scared the **** out of me, but it was the THUD my car made when I ran over it on the highway @ 65mph, and 1/4 throttle. Just a heads up.

 

I was driving to work today and when I got here I decided to check my commander and noticed that my knock reading was 98 This has me really concerned. I hadn't previously seen a reading above 50 after spirited driving, although my pfc is relatively new and I haven't checked it that much. What had me really concerned was that I raced someone home yesterday and was really gunning it in forth, really pushing it. I noticed a gas like smell at some point which quickly faded. After this run is when I saw the peak of 50 with the previous high being in the 30s. Anyway, I let the car cool down and idle for a while before shutting it off without anything noticably amis. When I started my car this morning though I saw a larger then normal cloud of smoke but everything else seemed normal. Anyway, there is a rather large bump on my way to work in the fast lane which gives me quite a jolt some times so I hope that is what caused the high reading during my otherwise leasurely drive to work.

 

My PFC will record a high knock level when I shift gears.
Either my trans or diff are loose and thus make noise.
They have become noisier over last two years.

This is easy to test. Place the commander on graph mode which also allows freezing the screen after the test.

 

One time, I had a 169 knock. I also hit a pot hole. My knock stays on an average of 20 or less...good tuning by P.P. Racing