My 99' Contour SE smells like exhaust inside the car. It only smells like this when the panel, defrost, etc is turned on. For a brief while, A/C worked fine with no smell. Now is doesn't matter which I choose, if I turn on the blower it starts to smell like exhaust inside the car. Any advice what it is?

I'd check the cabin air filter.

http://www.contour.org/ceg-vb/showthread.php?t=9589