...passenger side dash? When I remove the two plastic panels I can see a white plastic piece with a metal rod attached moving continuously back and forth on a plastic track? It is located on what would be the side of the center dash. Is something jammed in one of the air vents and it can't close? Any answers would be greatly appreciated- the noise is driving me nuts!

its a time bomb...idk i just felt like answering a question... :) oh but if you want a real answer then i suggest you go to a good mechanic to get it checked, or your lexus dealer if you gotsss the $$$$