[DaveBerry]

The exact thing happened to me with my previous car, a G35. I had a metallic clicking sound, once per revolution. I only heard it at low speeds. I took it to my tire shop for an inspection. When they removed the tire from the wheel, they found the inside valve stem nut loose in the tire. When rotating slow, it hit the metallic rim once per revolution. At high speeds, it was forced to the outside by centrifugal force.