Sorry for the time it took to get back with you. My buddy suggested cap, rotor and timing chain. this was before he knew about the mapp sensor. He also mentioned there might be a sensor in the ditribitor that might be acting up. When i told him about the mapp sensor issue he said to check the vacum lines for blockage or leaks.
08 TT FJC
82 Scrambler (Scraps)
81 Scrambler (Sassy)
69 Maro... next project when the Jeeps get done.....