Repetitive slapping noise under 2000 S

[eli cash]

Yesterday I noticed a fairly loud, repetitive slapping noise happening under the car, passenger side. It will not begin until I hit 22-25 mph and will get more intense the faster I go. I just looked under the car and it seems like the protective plate there (not sure what you call it) has come undone (not sure how). It don't think this is causing the sound, but it seems like they would be related since it's coming from that spot. This is under the passenger side, at about the halfway point of the car.

Any ideas? The car is "driveable" but the sound is loud and annoying. Obviously, though, I'm more concerned about what's causing this or if this could lead to some bad news in the near future.

[eli cash]

An addendum: the bottom protective plate is quite obviously out of place. Maybe 2 or 3 inches removed from where it should be. I would have taken a picture but I have left my phone at home.

[seningen]

Sounds like Aero works :-)

Try putting the panel back in place and see what happens.

mike

[eli cash]

Ok that was it. The plate has been removed (was splitting in half). Mechanic says it's not a drastically important part, but I'll probably get it replaced down the road. Sounded so awful, relieved that it wasn't something internal.