My truck never shacked only from 20-30 but it always did that and then yesterday it started to shaking from 40-50 I havent picked it up more than 50 so idk if it shakes on other mph butbi havent changed anything on the truck or havent put anything what could it be ? Thanks in advance

 

Shaking doesn't really explain anything but if you mean it feels like the transmission is slipping or bucking, then its likely time to change your spark plugs.

 

Most likely a mis-fire

 

x2

 

Maybe threw a weight on a tire.

 

Cause now its shacking all the time when I press on the gass then when I let go of the gass it shacks a little more