02 Lexus Gs300 Weird Noise..plz Help

[lv6l]

Hi, I Have A 02 Lexus Gs300 With 30k Milage. I Recently Found A Noise Comming From The Center Front Air Vents. It Sounds Like Somthing Is Stuck In There And Is Hitting Against A Fan. But If You Open The Glove Box And Stick You Ear In There You Can Also Here It In There As Well. Does Anybody Ever Had Or Know What I Mean? I Hope So. The Noise Is Really Bugging Me But It Seems To Only Last For About 15-20 Min. After Driving. It Makes A Noise With Or Without The Engine Turn On. But After Driving For About 20 Min. The Noise Will Stop But Come Back The Next Day. I Have A Certified Lexus And Its Up To 100k Milage But I Dont Know If They Cover This Problem But I Want To Ask You Guys First. Thanks.