You said you rebuilt the engine. Doesn't the distributor (cam sensor) need to be timed/synced to the crank position sensor. I think you need a scan tool to do this. Had a misfire condition on my '98 Durango that was intermittent. Don't remember the final fix, but I did replace the pickup in the distributor and replaced ignition wires that weren't all that old. Didn't retime it because I didn't move the distributor body. Another thing that caused some other varying intermittent problems was frayed wires in the upper steering column at the ignition switch.