I might be on to something here with al this rust. RUST! I have to wait till all this "crap" (Marvel Mystery Oil & some water absorbant)I poured into this tank of...don't flame...REGULAR gas!(another story). It's pinging so bad, it set the CEL! :~) After a few drives, I do notice a significant improvement in the cold temp driveability though with the rust cleaned out and I hope it's all or mostly fixed with the next tank of good gas.