Part arrived today, so I installed it. No troubles with install, and the TB was surprisingly clean. I shot out the opening for the IAC anyway, for good measure.

Truck started right up (which is a good beginning since it hasn't been run since this problem started), and idled at 3000rpms. The instructions said that it would do that, and to drive it up to temp, then drive it 40mph or faster for five minutes for the computer to reset.

I drove it quite a bit, and it is still running at 3000 rpms. If the rain stops, I'll disconnect the battery overnight and try it again (unless you all have another trick that is more affective?)