I don't know why you're complaining. The V6 Mustang
offers pretty decent fuel mileage IMO. I have a 03 GT with a Kenne Bell blower as my daily driver, I get about 18 around town about 22 on the highway, which is pretty frugal in my book. My Bronco struggles to get 9 or 10 MPG in around town, and is good for about 12 on the highway.
You should be getting 16-24 MPG with your car. Which isn't bad for a vehicle with a four liter engine. Gas is cheap. Even when it was $4 a gallon it was still cheap compared to what it costs in other places.