The fuel economy of a 2008 Ford Mustang varies significantly depending on the engine and transmission. There wasn't a single engine option. You'll need to specify which engine your Mustang has (e.g., 4.0L V6, 4.6L V8, etc.) to get an accurate MPG estimate.
Even with the engine specified, the MPG will also depend on driving habits and conditions. The EPA estimates are a good starting point, but your real-world mileage may differ.
