My 2000 cherokee with a 4.0 in it started randomly missing. Just starts acting like its running on 2 cylinders for a few minits every now and then. When it clears up it runs fine. In 2000 they started useing the coilpacks and no distributor cap. I have a spare coilpac and changed it out with no luck. crank sensor? 02 sensor? cam sensor? I hate to just start spending hundreds of dollors on parts thats not the problem. Oh and it has no codes stored when it does this. Any thoughts?

 

If it happens on a heat soak start its perfectly normal... its a hot sputter..