96 xj, 4.0

A little backstory. A month ago I had a no start problem. Replaced the CPS with one from my junked 95 xj. Ended up that my no start was caused by an o2 sensor wire shorting out. It ran fine so I left the CPS in there. Now...

The last two weeks I've been having a problem with shifting. It wouldn't happen all the time, maybe 2-3x a week. Basically I could be driving fine, and I'll stop at a light, and bam, no more shifting unless I manually do it. It stays in 4th and won't shift down. Usually happens on my way to work or home so I let it sit once I get there ,and start it up a couple hours later and everything will be fine.

After reading , I narrowed it down to the trans solenoids. Thinking that once they get hot, they fail. I could be wrong though.

Fast forward to today. Driving to work after 5 or so min, it stopped shifting. However this time if finally threw a CEL at me, code 43 for misfire. That code actually surprised me cause I've had nothing but power from this engine with no sign of problems.

Now I'm just wondering if all the problems could be related, maybe a domino effect from the CPS? Or any other insight anyone may have. Thanks