While that is possible, I'm not sure how it could be the PCM
More likely is that there's something in the wiring, and the wiggling and movement of you leaning on stuff, unplugging and pulling the harness changed something in an intermittent short.
If the PCM was internally shorted, unplugging an injector wouldn't change anything.
Inspect anything you touched or applied force to, while messing with injector 2
Especially if you was using the tipm or something as an armrest.
Have someone crank it while you grab wires and wiggle it.