slapping noise when windy

[Timmy the K]

when driving at highway speeds on windy days, it sounds like something is loose on the driver's side, like some plastic part of the body is slapping. I can't seem to find anything loose over there, it's driving me nuts. any suggestions?

 

[Black Moomba]

Have you looked on the roof or in the front fender wheel well ?

 

[4runner_2006]

check the plastic fenfer underlining..