HGM, agree it's probably the crank at this point. Although I'm wondering if my ignition is an issue that could be contributing to this as well now. Seems like a faulty ignition at certain rpms could create the same problems in having. I ready through the book, I don't know that there's any test for it except swapping it out for a good one that I don't have yet.

I think I need to try a known good P curve as well as a D or something else compatible and then I'll know if I need to buy an aftermarket ignition. Problem is where to get one of these to borrow

 

Question. If I'm able to get the rpm shake to shake at a higher rpm now, but stable consistent at 2000 while cruising and when revving and letting return to idle it's 2400 rpms then smooth by 2000 doesn't that confirm it's not the crank?

If it was the crank and the shake was consistent at 2000 then shouldn't it shake at 2000 rpms no matter what?

Just thinking about this today and technically if there was an imbalance I would think spinning at the offending rpm should repeat it no matter what. I need more diagnostic tools something's off here.