Maybe you have a problem with one of your knock sensors? Did you try the 110 octane? Try some 110 and see if you still have problems, try changing the sensitivity or frequency of the sensor to see if it makes a difference. Is it happening just before a shift? Can you hear the knock? Justin or Chris ,not sure which one, told me a trick of riding beside a jersey wall with the window down to help amplify any knock that might be happening that you couldnt hear otherwise.

 

Could be a knock sensor. I've thought about that but its a fairly low miles engine and I'm not yet ready to tear it apart and swap them out. May get there.

I haven't tried 110. Hard to find in my area, when I find it I will. I have tried some octane boost and it did reduce the amount of KR. Not the frequency and area of knock but the amount of timing being pulled. I have made a couple other changes at about the time I refueled, leaned it out again, so it might be that.

I have tried de-sensitizing the system in the rpm area I have a problem. Not much but it made no difference.

Aside from the day I installed the SC and drove it the first time with 87 octane in it, nearly 2 years ago, I have never heard the first hint of ping. Of course it is not the quietest truck on the road and my hearing is not what it used to be.

I have made several logs with transmission shifts and TCC lock being monitored. I can't definitively tie shift or TCC lock to all of the KR. Some like you mention... right before a shift.

I am going to start looking at older logs and see If this is problem has gotten worse or is on the same par that it has always been. This has never been a KR free combo. If its been on this level for an extended period I am not going to sweat it to much and move on to completing the tuning and work on it later. EDIT: Looked at logs back to the week I put this engine in. Fairly safe to say that it has had this problem KR spot from the beginning. See some bigger spikes now.