I have a 99TJ w/4.0L 5-speed. The problem is it has a part throttle surge. about 1200 rpm to 2200rpm it has a intermittent surge. It is not bad just enough to notice.
replaced plugs, cap and rotor helped some like %30 gone. It is not even like it is lean but I am open to investagate all suggestions. Vehicle has 84k miles.
Think it needs wires? it is slightly less noticable on low humiditiy days. I do not think it is a cylinder cutting out no backfiring all plugs looked good. Map sensor doin its own thing maybe? Wot it runs decent. This thing has me puzzeled.