Well, I got a little too excited. Turns out my PCM is actually bricked, even though the flash went through.

I'm not exactly sure what I did wrong, but 2 things that come to mind are:

1. I flashed a different calibration than what was in the PCM. It had an auto trans cal, I flashed a man. cal

2. Maybe I messed up when I tried to correct checksums.

I'm not exactly sure where I'm going from here. I'm still reviewing my options.