If the car had just been sitting in rain, my guess is the windshield. If you at all drove it even through a few puddles, it can be a hole.
Once the water gets under there it stays there. It takes a shit-load of water to have it come up through all that underpadding and foam. So either it's been saturated for a long time... or you have a windshield/vent leak and it's running under the dash and dripping on top of the carpet.
Like I said, once you have moisture under there it's game over unless you peel back the carpet enough to see what the situation is.
When I pulled all my carpets and under padding it was soaked. That crap is like a sponge and would literally take weeks to dry out.
Performance one step at a time.
Last edited by InfiniteDice; 10-03-2012 at 02:55 PM.