I have only owned one cj of this era, so I may not be of much help. Mine did develop similar symptoms. Under the dash in the fuse box was a blown fuse that controlled something in the engine compartment (I think a pump for the carb), I replaced the blown fuse and the problem went away. this could be several things, timing, clogged gas tank, fuel filters(theres one in the carb I think), ignition module going out. my current jeep did this exact thing this spring and it was the filters.