Why does the cool air coming out of my window unit a/c smell SO bad?

It's a Frigidaire 10,000 btu and is awesome. The MAJOR drawback is the smell of the air coming out of the unit when I turn the temperature up. When I have the unit on its coolest setting, it is perfectly fine, no nasty smell. But if I turn the temp up so that it doesn't blow as cold, the air that comes out STINKS!! I'm talking like the smell of stinky feet or funky cheese. I have tried using a dryer sheet in addition to the filter; but that has no effect. I have sprayed the filter with air freshener and cleaner with no luck. Please help me get rid of this nasty oder!!