[Pontiac4life]

I happened to mine, exactly like that, only when it rained hard. It was the weatherstrip under the windshield. It is under the cover of the space between the windshield and the firewall, where the wipers "rest". Of course, on the passenger side. This weatherstrip is there to avoid water coming in the A/C intake. If you figure out how to take the wiper arms out, only like 6-8 screws separate you from fixing it with some good silicone. Of course, counting it is a 97-2003 Grand Prix, like mine. Good luck!!