My jeep has had this issue pretty much since I have owned it and now is getting a little worse and I am finally getting around to working on it. Its a 258 with the nutter bypass, upgraded ignintion coil, cap, button, wires, etc. Sometimes when I am driving it will just shut off. I can push the clutch in, hit the switch, and it will start right back up while rolling. lately half the time it does it multiple times in a row and will back fire a few times. also sometimes it will go down the road and just fall on its face. motor stays running but every time I hit the gas it bogs. then like a flip of a switch 20-30 sec. later it will be fine. issues seem to be more prevalent in the mornings when the moisture is up in the air, foggy, etc. The foggy morning last week when leaving work it did not want to start, ran like crap from the get go, backfired, etc. I drove home from work (only 6 miles) it ran bad the whole way. went back out at 3.5 hrs later (when the sun was out good) to pick up my daughter from pre school and it ran fine all the way to Lexington and back. Has anyone dealt with this??