So yeah, I agree it seems to be the PCM.
Today I drove without touching the a/c. It was fine through highway and some lights until I turned the car off. Turned it back on and didn't drive one block before I clearly noticed a change. Even my transmission was shifting weird a couple of times. At a stop, if my car was in gear, it would jolt forward slightly shortly after stopping.
Going to order a PCM and hope it fixes it. Otherwise it could be a ground issue.
Have you verified the engine temp? As in a thermal gun pointed at the thermostat housing? All LHs have differen't points on the gauge they operate at. A new sensor can change it.
Also, that surge forward may be it shifting into 1st. What other changes did you see?