My truck is an 05 f150 5.4 4x4. When im driving down the road on the throttle and let off and coast for approx. 20 to 30ft and when i get back on the throttle something slams hard like a really bad ujoint but i have had the ujoints changed and it still has the problem. Has anyone had this problem or know what i might can do. I hope i explained this well enough.

 

My 05 stx v6 did that from time to time. Never did figure it out.

 

Yeah dont happen everytime. Its weird