I feel your pain!

Took my 1997 JGC to the dealer due to loss of power, they told me my exhaust was plugged, I replaced the cat - $250 and went back. The local Jeep dealer could not find the problem; said everything looked great, even did a smog test, passed with flying colors!?? They suggested new PCM, which I did; out $250, it was temp fix then more of the same, burned the cat out in 2 months!

Independent mechanic couldn't figure it out either. I've replaced both O2 sensors, the TPS, CPS, ignition coil... in total $1500

I have tried everything you've listed and right now I am thinking the problem might be the fuel injectors because of the intermittent problem of excessive fuel getting through eventually burning my cat.

As I am thinking this through, this seems to line up with the overhead computer read-out of poor mpg especially from standing start 5-7mpg, regular take off speed; so the gas is pouring through. On a level rode it runs like a top 24mpg and descending it ranges from 30+ to 50 depending on the grade.