So I have an HEI 350 in my FJ40. It has been running like a top for the last two years and now it has developed a miss. I have checked everything! Wires, plugs, cap, rotor, fuel filter(just in case). Its odd though....runs smooth like new then all of a sudden it runs like I am missing a cylinder. It does this all the time now. Runs great at times then poorly at times. More bad then good though. Does anyone have any thoughts on this? I could be there at a light with it running awesome then It will just change moods on me and run the rest of the drive like crap. Can't see it being a vacuum line as the engine hardly has any on it. No emissions crap either as the engine is from the early 70's. Anything anyone has to offer would be great.