On our '97 4Runner, we've noticed a black residue all over everything lately. You wipe the dash off, and it's just black. It's not brown, it's black. For the most part, the windows are up as the wife drives it and doesn't care for the windows down. My neighbor had mentioned something of a possible antifreeze leak similar to something he experienced years ago in his Buick. Anyone ever had this issue before, and could there possibly be some leak somewhere that is blowing crap through the vents into the vehicle?