Hard to find right away sucks.
Fuel pressure constant and is the leakdown good???
If not fuel then ignition and timing have you checked all the parts???
Since it does it straightens out and then does it again it has to be something intermittent.
Have you checked for loose grounds to the engine passenger side of the block there is a bunch in one spot. Remove and clean.
Cracked dizzy cap grounded wire in the dizzy or to the dizzy???
You know with the wires if it is intermittent it could be anything so a good visual inspection is warranted and you may get lucky and find something easy.
Just a few thoughts
89 2.5 TBI, 4" RC lift, 1" Booms, SYE, Adams Driveshafts front and rear, Ford 8.8 with 4:88s, BFG 33X12.50X15, and a ton of other stuff.
AF Jeep Club Tail Number 184