Please pardon the newbie and if I am repetitive I'm sorry but I've searched the feeds and can't find anything on this.
My story began 2 weeks ago when I was on the trials (Saturday) my TPS light came on. I shut down and cycled through the ignition and it went off. No more problems until on the way back home Sunday night (3.5 hours to the house) it came back on as I was driving 3 different times but went right back off. No issues Monday going to and from work. On Tuesday I went to work no problem but when I went to leave for lunch my electrical system went haywire. Jeep won't start, when I turn the key it acts like I am turning the key on and off... I am pulling codes p0513, p0642, p2122 and p2127.
I have searched everywhere looking for you a loose ground or something that would cause all of these faults to happen at once and nothing is making sense. Battery checks out, alternator as well.
Any insight would be duly appreciated.

 

Looks like a difficult problem to help troubleshoot. Here's a quick description for the those codes on a 2010:
The latter three codes have 5 volt issues in common. That could be a lot of things, from a bad sensor to wiring problems, even the whole PCM. Consider any recent repairs or mods first, often that can lead you in the right direction.

The P0513 code stands out from the others. The PCM failing is common to all these codes. This code might be related in another way, or maybe it's a separate issue. Suggest trying another key.

There are grounds in the engine compartment close to the fenders. There's another on the drivers side near the OBD connector (drivers left leg). A generic trick is to disconnect the battery for a few minutes and see what codes come back, and if the symptoms change. Sometimes a complete power-down and reset gets stuff to self configure and recover. The self diagnostics and the manual are good, but not perfect.

There's pages of detailed troubleshooting for each of these codes. Space and time was limited. Hope this helps, stay in touch.