* Vehicle condition: A well-maintained truck will generally get better gas mileage than one that's neglected.
* Driving habits: Aggressive driving (rapid acceleration, hard braking) drastically reduces fuel economy. Gentle acceleration and consistent speeds improve it.
* Load: A heavy load will significantly reduce gas mileage. An empty truck will get better mileage than one towing a trailer or carrying a significant amount of cargo.
* Terrain: Driving uphill or in stop-and-go city traffic will result in lower fuel economy than driving on flat, open highways.
* Tire pressure: Properly inflated tires improve fuel efficiency.
* Modifications: Aftermarket modifications can either improve or worsen gas mileage.
Given all these variables, it's difficult to give a precise number. However, you can expect very low gas mileage, generally in the range of 8-12 MPG (miles per gallon). It's not uncommon to see even lower figures, especially in less-than-ideal conditions. Think of it as a truck that drinks fuel rather than sips it.
You should also consider that this is a relatively old truck, so its fuel efficiency will likely be on the lower end of the already poor fuel economy range for a vehicle of this size and engine.
