Random misfire and ticking

John MacMoyle · November 1, 2020

So I am at a loss here. I have had an issue with my 2012 Silverado 1500 LT where cylinder 1 eats spark plugs for whatever reason. No big deal I just keep a spare and swap them when I need. That’s happened 3 times since I’ve owned it. The other day I am on the highway running probably 75 when it started running rough, tapping and the check light started flashing. The tapping was like a pen on a desk not a knock. I pulled right off and checked the oil and no. 1 plug. Oil was a lil low and I swapped the plug but the problem persisted. I drove it another 15 miles doing 55 and the light changed to solid and the misfires and tapping went away. I still have a light on solid reading the codes p0300, p0466, and p0300. I am inclined to change plugs and wires along with an oil change. I still have oil life left and is full synthetic and I did plugs and wires a few years ago. Has anyone had similar experiences?

CamGTP · November 1, 2020

Is that cylinder 1 plug always covered in oil or have a bunch of white/grey build up on it when pulled?

I say that because cylinder 1 is an AFM/DoD cylinder, so it shuts off when it goes into V4 mode. It's pretty common for one or more of the AFM cylinders to start burning oil and fouling spark plugs.

The code P0300 means it could be a cylinder or multiple. You'd want to hook up a scan tool with live data to see what cylinders are reporting the issue.