Fuel Air Metering

I own a 1996 Ford Thunderbird, once in a while the check engine light comes on and everytime I get it checked out it tells me it is the fuel air metering, I have no idea what that is...I am trying to figure out how to fix this...also, my front headlights are starting to fog over, do i need to replace them or can I sand them off or take them out and clean them....also is there a certain kind of paint or whatever that I can use to fix miminal, noticable scratches on paint, it is really expensive to get it repainted....I really thank whoever can help me.....
Dameon