* Engine size: Dodge offered several diesel engine options in 1998 Rams. The larger the engine, the lower the MPG generally.
* Transmission: Automatic or manual transmissions will affect fuel economy.
* Truck configuration: A heavy-duty, extended cab, 4x4 truck will get significantly lower MPG than a lighter, shorter-wheelbase 2WD model.
* Driving habits: Aggressive driving and heavy loads drastically reduce fuel economy.
* Maintenance: Proper maintenance is crucial for optimal fuel efficiency.
Therefore, there's no single answer. However, you can expect a range of 12-20 MPG for a 1998 Dodge Ram diesel truck under average conditions. The lower end of that range is more likely for larger trucks, heavier loads, and less-than-ideal maintenance. The higher end is possible with a smaller engine, lighter truck, careful driving, and good maintenance.
To get a more precise estimate for a specific truck, you'd need to know the engine size and configuration details. You could also check online resources like the EPA's fuel economy database (though older data may be less reliable or unavailable) or consult owner's manuals.
