<human>:  How do I maintain my car to improve fuel efficiency?
<bot>: To improve fuel efficiency, you should regularly check the air filter, replace spark plugs, and maintain the correct air pressure in the tires. Regular oil changes are also important. Make sure you use the correct type and viscosity of oil for your vehicle. Additionally, you can consider tuning up the engine, as a poorly tuned engine can reduce fuel economy. Finally, try to drive at lower speeds and use the most fuel efficient gear.