96 xj sport 4.0l ecm intermittently cuts out

I've done a brief search of the forums but have not seen my exact problem.
I've got a 1996 Jeep xj sport 4x4 4.0l 5 speed with 235k miles. Good running jeep but recently (about a 3 weeks ago) developed problem. ECM intermittently cuts out for brief moment. The reason I say it's the ecm is my cat converter was removed a few years back so the check engine light is always on. When the problem happens, the check engine light clears like the ecm has been reset. It then takes several drive cycles for the light to come back on. The radio and lights are not affected, but seems like the ignition system is turned off for about half a second. It has happened under different circumstances but seems to happen more often when accelerating. I've not done any investigation but will take a look at it this weekend. I'm wondering if anyone knows if there is a common issue (bad ground, etc) that causes this or is the ecm going bad?

The more likely explanation for the symptoms is that there is an electrical issue causing a voltage drop to the PCM or that there is some type of short circuit.

If you re-boot the PCM, all saved data is erased, including all the Check Engine Light codes. There is a manual method to re-boot the PCM, and loss of voltage will re-boot the PCM. The end result is the same.

Installing a fresh cat converter and fresh O2 sensors will pay for themselves with increased gas MPG's. I would guess you are seeing about 11-13 mpg's right now.

That's kind of what I'm thinking, but just wondering if there is a location that commonly causes issues. I found a way to test the ecm for high ground resistance but just wanted to make sure there isn't a common failure point that I'm unaware of. It seems like every problem I've ever had was encountered by someone else so I'm hoping the same goes with this issue. As for the mpg, I average 17-18 and I track my mpg on all my vehicles religiously. I saw about a 1-2 mpg drop when they switched to the 10% ethanol but there was no noticeable change when I pulled the cat.