I have a 05 liberty that will for lack of a better word ,buck at 2500 RPM every time, you can drive up to 2400 RPM and it's smooth and strong ,at 2500 it bucks like a gas motor with a bad plug wire, if you push the accelerator past 2500 it smooths out again. I have had it to the Jeep dealership and they have no answer for the problem, I stoped by a good diesel shop and they said that they could not accesse the comp. with there scan tool , has any one had this problem before or have a good guess as to what is going on.

 

How well does it start in the morning, plugged in or not? Also, the check engine light come on or any codes?

 

The Jeep starts good in all temps down to 20F not pluged in. It has never shown a code