Water Leak

Hi, this is my first time asking a question on here, so I'm hoping someone can help me. I have a 1992 Grand Am, and whenever it rains my front drivers side carpet gets wet and I have to take out the floor mat to get it to dry. My car always smells from being wet. Any ideas why and where it could be coming from. I've sat in the car during rain and can never see any water coming in. Thank You.

there is a seam in the firewall, just above the top of the gas pedal behind where the rack and pinion mounts that is common to split and leak