Why is the gas mileage of my Ford Focus decreasing?

I have noticed that my Ford Focus is getting worse gas mileage than when I first bought it. What could be causing this and how can I improve it?

There could be several factors causing the decline in gas mileage. One common reason is that the tires may need to be properly inflated. Make sure to check the tire pressure regularly and fill them to the recommended level.

Another possibility is that the air filter may be dirty or clogged. This can significantly impact the fuel efficiency of your car. Consider replacing the air filter if it has been a while since it was last changed.

You may also want to check your driving habits. Aggressive driving, such as constantly accelerating and braking, can waste fuel. Try to maintain a steady speed and avoid rapid acceleration and braking.