[UmDaMan]

Did you use a routine dose of injector additive in gas tank? I do, and on my Lexus (262kmi) I don't burn any oil, and, when I scoped the cylinders they were all very very clean. Of course I cannot see what the rings look like. In your case of a carbon build-up leading to excess oil consumption, that would almost indicate maybe a cracked oil control ring or skirt? Or maybe a small defect in cylinder wall that is allowing more oil into chamber?

Did you happen to scope the cylinders before doing the chem soak? Did all the spark plugs come out looking excatly the same?

I do not normally add any fuel additives. I think once I added an injection cleaner a couple years ago. Yes, I checked the cylinders. I’m not entirely sure what a bad one looks like, but from what I observed, they all appeared to be in good condition. I also noticed a performance improvement after completing the treatment. I doubt I have a cracked oil control ring, because after the treatment the oil consumption was greatly reduced. My engine has 175K on it. So I would think there might be some normal oil burn, or it maybe just need another treatment to really clean them up. I did not notice any spark plugs looking any different than the other.