Hello! I just bought my 2004 Mustang Convertible. And we just had a pretty heavy rain last night, so I came out this morning to find that the floor behind the passenger seat was filled with about 3 inches of water and my speaker was thumping weird noises even when no sound was playing. I checked behind the back seat and noticed there was some water in that little flap that's suspended under the window. Is this a common problem? It's only on the passenger side that there is leaking. This is my first mustang and any help would be appreciated. Thanks!