Car Tech forum: 96 Jeep Grand Cherokee Timing/Grounding Issue?

I recently bought a 96 Jeep Grand Cherokee Laredo and other than the cracked exhaust manifold everything ran great. I drove it for about a week and a half with no problems. On the way home one night it started jumping and missing and when i came to a stop it bounced idling from 150-650 rpm. A few minutes later it went right back to normal and i drove 2 hrs home with no problems. The next day my dad and i replaced the exhaust manifold and it ran fine until later the next day when it did it again and it has continued to start missing more and more since at random times. I looked under the hood one night in a dark spot to look for any sparks and sure enough there were flashes from every spark plug and 1 spot on the distributor cap. New distributor cap, spark plug wires and spark plugs today and the problem still persists. The sparks now only come from the 1st wire and somewhere near the 3rd but I cant quite pin point it.

If anyone has had this and figured it out please help, this is my only way of transportation and jerking at 15 MPH down the interstate isn't very good on my job security.