I bought a 2005 f150 king ranch 2 weeks ago with 93k miles. Started to notice at 45 to 55 mph if i let off gas and get back on it slowly it feels like the rear wheels kind of bounce a little for a sec and goes right back to normal after that.. Usually occurs more when im going up hills more than going straight or downhill? Also occured today going 60 mph and pressing resume button on cruise control. Never experienced any tranny issues on any of my previous cars so idk what tranny issues feel like.

 

Could be a coil breaking down. Or you are filling the torque converter clutch applying and locking up. A trans service my be in order.

 

thanks man. I have heard mixed things about transmission fluid changes. Someone told me it could make the problem worse?

 

Fresh clean fluid cannot make things worse. What happens is people are having issues and hope a fluid change fixes it. When the grand fails they blame it on the fluid change.
Old wives tale.

I would suggest that you need a good mechanic to drive the truck so they can actually feel the issue and start diagnosis.

 

Clean MAF and throttle body, and give it a new fuel filter. Do you have a stock paper air filter in it? How does the foam around the air filter tray look?

 

How big of an issue is it to you? Sounds like it could be 1000 things. Axle warp, bent rim, unbalanced tire. Slip yoke or driveshaft problem, axle shaft problem, ring and pinion problem. Worn out suspension. Rough roads. I need a little more to info to narrow it down.