When a vehicle is in four-wheel drive, the power from the engine is distributed to all four wheels. This requires more energy than when the vehicle is in two-wheel drive, as the drivetrain has to work harder to turn all four wheels. Additionally, the added weight of the four-wheel drive system can also contribute to decreased gas mileage.
The decrease in gas mileage when using four-wheel drive can vary depending on the vehicle and the driving conditions. However, it is generally recommended to only use four-wheel drive when it is necessary, such as when driving in slippery conditions or off-road.
