I bought a 2006 Kia Sorento new. I have not had any major problems until now. In the last few weeks it has begun vibrating when I get to around 15 miles an hour. Not 10 or 20 but right around 15. Any other speed and it's smooth sailing. I've bought 2 brand new front tires, new rotors and brakes. I've been told it's my front u-joint. The mechanic raised the car and took me under and showed me that there was "play" in the u-joint. I don't have the money to experiment. What could it be?