me when idling sometimes right after a fill up at Smith’s. My mechanic cousin said to stop using Smith’s and insist on the brands like Chevron that have additives. I filled up at Chevron and I think/hope/fingers crossed it seems to be doing a bit better. So IF that was the cause then I did get a bad batch from Smith’s.

This seems to corroborate, but I am always a little skeptical of too simple of answers when it could be other things.