Car Maintenance for Better Fuel Economy | Exxon and Mobil
Upgrade your motor oil. You can help improve your gas mileage by as much as 1–2% by upgrading the manufacturer's recommended motor oil. For example, using 10W30 motor oil in an engine designed to use 5W30 can lower your gas mileage by 1–2%. Using 5W30 in an engine designed for 5W20 can lower your gas mileage by 1–%.