i know this may sound wierd but i am deployed overseas and if i was home i would have an idea of what my wife is talking about. i have a 1996 xlt bronco with a 351w. the problem i am havng described by my wife is when the speed reaches 55 mph it shakes really bad thought she had a blow out it shook so bad stopped on the interstate and checked. before that she said she smelled something burning i dont know what this could be i had the recalls fixed and i had both ball joints replaced and the back brakes replaced brand new from the dealership. the ball joints are tricky on the 1996 takes like three four hours a side right and they have to do alignment when they finish anyways right so that is why i rule out the alignment i know she didnt do anything drastic like run over a cow she only drove it twice after the new parts where installed. maybe someone might have had the same problem please if you could reply i am kinda worried about my trck and my wife. more the truck lol jk.