Ok so I was driving down the highway. Got off and my 99, 4.0l started to shutter lightly. As a drove it cleared up next it got worse. Then worest at every light every that. Then it stop and smoothed out. Didn't have any more problem with it.

Aslo it would shutter at 45mph and shift through and be fine again.. any ideas??

I'm think coil?

 

check the coil see if its craked cus they tend to do that. Also check ur plugs and plug wires. A plug wire could be arking out against the engine giving u ur shutter. Wouldn hurt to change the cap and rotor too!!!!! i just changed my cap, rotor, and coil for bout 50 bucks!!!