Originally Posted by
vettemakesemwet
History misfires don't clear for awhile, or until codes are cleared. As for the knock sensor, those are some of the most common issues with the gen3 engines. My sierra has had the CEL on for knock sensors for a couple years. Is a daily driver no mods so I don't care as of yet. If one of the sensors is bad, do yourself a favor and change both of them along with the KS sub-harness. KS#2(rear one) is most common for failure due to water contamination. GM had a bulletin out years ago directing to make a V shaped dam with silicone to route the water away from the rear sensor to help prevent this. I usually still do this when I get a gen3 with KS issues. Maybe I should fix my own someday....
Misfires at idle could be a number of things. Watching the log it is not adding the misfires to history counters, so I would not pursue that unless you can feel them or it is hurting performance. Unless of course you have nothing better to do....lol. If it won't log them to history, it most likely won't set a P0300/CEL.
Is it a DBW or DBC setup for the throttle? Either way, might try a search for hanging throttle. Haven't gotten into too much of that yet, still learning.