Little more history what led to theis adventure. Last month I was in the Death Valley area 4x4ing, when all the problems started. I had noticed that the jeep was running rough while running down the black top. While driving at hwy speed I could smell something burning. I pulled over to see if there was an unusual oil leak-none. While on the trail the jeep would backfire, sput / spit while underload (going uphill in 4x4 low, 1st gear). Very consistant. Had trouble starting after taking a 15 min break for lunch. I first thought it was a vabor lock (I believe I had vabor lock while hard wheeling in last summer, temp peaked out). This is why I installed an electric fuel pump inline with the mechanical pump. Mech pump is sill working OK. Electric fuel pump..backup. Anyway hope this helps with the dianostic.