Does changing your oil give you better gas mileage?
Simply so, do oil changes affect gas mileage?
Running an engine on old, sludgy oil will cause a decrease in fuel economy. Without the right viscosity, the oil loses the essential ability to get where it needs to go in the engine. The engine runs hotter and less efficiently, robbing the engine of both gas mileage AND horsepower.
Also asked, does synthetic oil give you better gas mileage?
Synthetic motor oil can help to decrease the chance of your vehicle running out of gas faster than normal. Less-viscous oils flow with much less resistance through the motor and thus provide less friction to motor parts, thus improving the car's fuel MPG.
The most common purpose of a performance tuner is to increase horsepower, but chips can also provide better fuel economy, sharper throttle response, and higher torque for towing heavy loads.