My TJ has an occasional cylinder 1 misfire indicated by the check engine light and an occasional lurch at highway speed.  I have noticed the misfire when cruising at highway speed after driving about 20 minutes and feeling a sudden lurch, or when sitting at a red light idling.  The engine runs fine aside from the occasional lurch and running rough at idle.  I suspected a sticky lifter so I ran Sea Foam in the oil for about 2k miles and then changed the oil and filled with 10w-40.  I never notice