How can I improve my Ford Focus's gas mileage?

I have been noticing that my Ford Focus's gas mileage has been decreasing recently. What are some ways to improve its fuel efficiency?

One way to improve gas mileage is to make sure your tires are properly inflated. Underinflated tires can decrease fuel efficiency. You can check your car's manual for the recommended tire pressure.

Another way to improve gas mileage is to avoid idling your car for long periods of time. If you're stuck in traffic or waiting for someone, turn your car off instead of letting it idle. This can save a significant amount of gas over time.

Regular maintenance is also important for fuel efficiency. Make sure to follow your car's recommended maintenance schedule, and replace the air filter if it's dirty. A clogged air filter can decrease gas mileage.

Try to drive at a constant speed on the highway, as frequent acceleration and deceleration can decrease fuel efficiency. Also, avoid carrying excess weight in your car, as this can also decrease gas mileage.