* Engine: The E250 came with a range of engines over the years, from V6 to V8 options, and their fuel efficiency differs substantially. Larger engines will have lower MPG.
* Transmission: Automatic or manual transmissions will affect fuel economy.
* Cargo Weight: A heavily loaded van will get considerably worse gas mileage than an empty one.
* Driving Conditions: City driving yields lower MPG than highway driving.
* Year and Model: Fuel efficiency standards and engine technology have improved over the years, so older models will generally have lower MPG than newer ones.
* Maintenance: Proper maintenance impacts fuel efficiency.
Therefore, there's no single answer. To get a more precise estimate, you need to specify the year, engine, and transmission of the particular E250 van you're interested in. Then you can consult the owner's manual or resources like the EPA's fueleconomy.gov website (for US models). Even then, the figures will be estimates, and your actual mileage may vary.
