Years back on my Pontiac G8 GT, it had a problem common among the model, the weep holes in the door were also the holes the push pins went in to hold the weather stripping on the bottom of the door. They were notorious for getting clogged with junk. Every now and then, especially after a lot of rain, I'd hear a sloshing sound in all the doors. I'd have to pull all the weather stripping off the bottoms, which was nasty it was always slimy and dirty, and let the gallons of water that accumulated drain out.