2000 LS400 with 60k miles. Mysterious vibration has developed in front end when temperature is 45 degrees, or lower, especially upon initial start. I feel the vibration from the road up and very slightly with the steering wheel. Vibration lessens, but does not go away entirely, upon warm up and driving several miles. I rotated and balanced the tires and no change. The front rotors were turned but I don't think it is a brake issue. I am not a mechanic and there are so many potential causes, but I suspect either motor mounts or something in the engine causing a slight imbalance. I do not feel any vibration when full speed crusing on the highway. I have searched the Forum but have not stumbled upon this precise issue. Anyone else have an experience similar to this? Many thanks for your replies.