I bought a '94 Land Cruiser on Saturday in West Virginia and drove it back to Nashville (550 miles). The vehicle drove great, no problems whatsoever. Sunday I went to get gas and at a speed of about 45mph it started shaking. The shaking lasted for about 30 seconds. I was afraid a tire was about to fall off so I pulled over into a parking lot. I drove it around the lot while my father stood outside the vehicle and watched. The tires seemed fine. He got back in and we continued on to the station (including driving on the interstate at 60mph). As I was exiting the interstate I felt a minor vibration. I probably drove it another 30 miles on Sunday without incident. Does anyone have any ideas as to what may have caused the vibration?