I had a spare PCM with a busted case from another junkyard vehicle, so I decided to swap them to see if anything changed. The second PCM seemed to let the engine accelerate slightly faster than the first, but still no improvement over the way my stock 4.2 accelerated (I have a hill that I use to "test" the acceleration).
After I got back from that test drive, I pulled the codes from the second PCM. They were the same as the first: 12, 75, 73, 35, 55.
1984 CJ7 Laredo
4.0 I-6 / T5 / D300 / D30 / D44
Black Diamond 3" lift, 33" tires, 4.11 gears