I finally got one of those bluetooth obd tools and the torque app, and decided to drive it around while watching the O2 sensor and the short term fuel trim.
Drove around the block a few times and all was well. No issues. No stumbling, nothing apparent. Decided to bring it out on a bigger road with a little higher speeds. As I was going up the first hill, the O2 readings flatlined. It hesitated for a minute, then the PCM switched into open loop mode.
So in my mind, I started thinking the O2 sensor could have a temperature dependant open or short circuit. Sure enough, a few minutes later, P0130.
I'll swap the O2 asap. I was also trying to listen for the squeaking noise that I heard the last time it stalled. I realized that as it was stalling I decided to roll down the window. I noticed today that the brakes have a slight squeak to them, which I probably heard only when I rolled down the window, and thought may have been associated with the stalling.
Anyways, well see what a new O2 does.