I had this same problem. You know that air intake on the hood cowl? It has that grill over it? Take that off. Look in there and see if the drain is clogged. If you can't see debris from there, open the hood. On the fire wall will be the rubber drain tube. Take it off and see if it's clean. Mine was clogged, so I stuck a hose in it and blasted all the garbage out. At the bottom of the drain, there's only a small slit for the water to drip through. I though this was stupid because it traps dirt in there. I took a razor knife and made a larger hole. Haven't had a problem since. If this doesn't help, the windshield seal may also be the problem.