Ha your right there. Lol. While oiling I found a few of the oil ports. Not to say I found them all but I found most for sure.
Yes I cleaned top and bottom for the race and everything I could get to. It’s perplexing. Like you I figure one problem at a time. Never worked on a sewing machine before is slow and easy. The spring that sits on the end of the presser foot lever assembly that fits on the end of the assembly and rests (I think on the inside of the tensioner ) is a bit wonk in where it fits. Kinda like a negative battery spring that is pushed out of position. If that makes any sense. As you say I don’t think that is the problem at hand. Again the dogs do move the material very nicely with no help from me. It’s as though there is a throw problem. The lever moves up and down and the mechanism moves freely but maybe not enough to the longer stitch side. No clue.