I'm calling it a night for now. I'll resume this in the morning. I ran the engine with the radiator cap off, and I can't see how there can still be air in the system. I had the cap off the T-fitting when I started it up, and the coolant came gushing out. So, I closed it but left the radiator cap off.

I took a look at the TPS. It's fine. I did notice that when I turned it to where the engine wouldn't kick down (with timing jumper set) the lope went away, but the high idle remained. Also, when I unplugged the TPS it did the same thing. If the problem is in the cooling system, can applying throttle, unplugging TPS, etc. cause it to go away? I don't have a good enough understanding of these machines to answer that.

Haven't checked for vacuum leaks yet. Still, it has been my experience that a lopey idle has more to do with the cooling system than a vacuum leak. Whenever I've had vacuum leaks it has caused a high idle, but not lopey.