Actually, I just *bought* the 'Stang to save on fuel. I know its not an economy car but it gets twice the fuel mileage my truck did.
I love the car and I could not afford to sell it, either. I also have a 1966 I love and would sell only as a last resort. It's a small mini retirement fund or drastic emergency fund.
If gas gets high enough, I might buy a Focus or something to drive most of the time and save my Mustang GT for special occasions.