* Driving conditions: City driving will yield significantly lower MPG than highway driving. Stop-and-go traffic drastically reduces fuel economy.
* Vehicle condition: Proper maintenance (tire inflation, tune-ups, etc.) impacts fuel efficiency. A poorly maintained vehicle will get worse gas mileage.
* Payload and towing: Hauling heavy loads or towing a trailer will dramatically decrease MPG.
* Driving style: Aggressive acceleration and high speeds reduce fuel economy.
Considering these variables, you can expect a range of 10-17 MPG for a 2003 Dodge Ram 1500 with the 5.7L engine. The lower end of that range is more likely in city driving or with a heavy load, while the higher end is more achievable on the highway with a lighter vehicle and conservative driving.
To get a more precise estimate for a *specific* vehicle, you should consult the owner's manual or check online resources that provide user-submitted fuel economy data, such as Fuelly.com.
