So I have an 04 fx4 with 90k on it and I noticed just recently when going up a hill and keeping a steady foot on the gas that when it down shifts from OD to drive and then back to OD again it feels like you drive over a small amount of the warning marks on a side of a highway. Thats the only way I can explain it because I thought I was hitting something in the rode but after a couple times of this I knew it was something with the truck. I have noticed it when I am going 55-60 and it happens more with the cruise on because of trying to maintain the speed. Hopefully its some easy fix.

 

Low grade misfire. With 90k, it's due for new spark plugs.