Setting the caster is easy. Just get a digital level; something like below for $40. Set the axle up up on jack stands level. You can check the caster off the top the top ball joint. You can easily get within .1 to .2 degrees and that is good enough for a jeep. There is no camber adjustment and you can measure and set toe-in with a tape measure.
My advice too. Don't think it applies to your axle, but if you have a nut on top, just set a socket on it to provide a flat surface for the level. Have guys locally that do axle resizing all the time.
Regarding the PCM issue, suggest you join CJ-8.com and pose the question over there. Bunch of friendly guys which can at least point you in the right direction.
Other option, but be prepared for rougher language is pirate4x4.com. Larger crowd though. Just make sure you have the engine size/source along with PCM number.
Now, if you want to leave the jeep someplace safe while awaiting parts, my daughter is just east of Knoxville and may be willing to let you park it over there. Her father-in-law may also be able to help you out with contact for someone on the PCM issue. All I would need to know is where the engine and PCM number (located on the PCM).
However, it sounds more like a grounding issue with the PCM. Like maybe a wire getting pinched or coming into contact with the manifold when the body is getting twisted.
