My truck when ever go about 45 to mph has a slight buck that I can feel under me. Usualy when I jump on the freeway I cant feel it. If I slow down to under 40 it goes away. I haven't noticed any loss in power and it still drives fine it just want to buck and miss around this speed coud it be a torq converter? bad cat? its a 95 xj country 3 inch lift

 

I had this issue when I first brought my '96 home. I replaced my worn-out shocks and it went away. Granted, it's all stock with no lift.