Have recently began to notice an odd vibration. The car is one of the smoothest vehicles I've owned and this began about 3-4k ago, have 15k now. The vibration is intermittent and usually occurs at 65-70 mph. Do my own maintenance at shop and rotated and balanced tires, the rears were out 1/4 ounce. they all got rebalanced regardless but vibration still exists. Now this isn't road feedback or some complete anal concern, this vibrating is felt in seat, steering wheel etc, very noticeable. Definitely a drivetrain vibration that is cyclic in nature. Has anyone had any vibration issues? Im thinking the clutch system that transitions vehicle from electric to mechanical. Just a thought though, any feedback appreciated.