Today i was driving down the road at about 40mph when the truck all the sudden starts jerking really bad jumping up and down with the steering wheel going left and right back and forth. i let off the gas and it stopped, but when i got back up to 40mph it continued for a while. Ive noticed that it does this more frequently when i hit a bump in the road. and its not all the time, sometimes it drives normal. couple hours ago a friend was driving in front of me and when it started doing it he said the passenger side tire was jerking left and right rapidly and the truck was just rocking with it. They said it looked almost as if the tire was about to fall off. I jacked it up and spun the tire as well as turned it left and right but couldnt see anything physically wrong. Could it be the steering shock? or the panard bar? Truck has a 4.5" icon lift with 35's. stock steering shock. no upgraded steering stabilizers. Any help would be greatly appreciated.