I just began to notice a rattling noise on the front passenger side of my '03 Silverado. It sounds like windshield chatter. I checked the wiper arm and everything is okay. The noise doesn't occur until I'm at 70 mph. I'm not sure if it would be my wheel well rattling or something to do with the air vents or maybe some random piece of plastictrim. Has anyone come across this problem or know what it might be?