two things my car did this a bit and there were two causes. First I have the 3.7 AWD and the tire were worn unevenly LF 4/32 RF 2/32 LR 5/32 RR 5/32 and the Right Front would vibrate occasionally when I put new tires on the car it went away. This car the tire need to be within 2/32 of wear if not you can get awd issues maybe the vibration is caused my this.The other reason was my lane keeping system sometimes i think there is a vibration on the road but usually its the lane keeping system.