Why Is My Car’s Fuel Economy Getting Worse?

Updated on October 26, 2023
Why Is My Car’s Fuel Economy Getting Worse?

If you’re noticing your vehicle’s fuel efficiency worsening, don’t worry—you’re not alone. As vehicles age, fuel efficiency often decreases, but it’s not entirely out of your control. Below, we’ll explain some possible reasons why your car’s fuel economy is getting worse and offer some simple solutions.

Do You Have Old Spark Plugs?

Believe it or not, something as small as your car’s spark plugs can be a major culprit in declining fuel economy. Over time, as spark plugs wear down, they may misfire and cause your engine to burn more fuel than necessary. Thankfully, replacing your spark plugs is an inexpensive and relatively simple fix that most car owners or a trusted mechanic can do.

Are Your Tires To Blame?

Your tires can also affect your car’s fuel economy. Here are a few tire-related factors that can impact your fuel efficiency:

  • Tire size: The size of your tires may be the issue, as there’s a strong connection between tire size and fuel efficiency. Consider smaller tires with a lower rolling resistance for better fuel economy.
  • Tire pressure: Under- or overinflated tires can negatively impact your car’s fuel efficiency. Monitor the tire pressure and follow your vehicle manufacturer’s recommendations.
  • Tire age: As tires age, they lose their tread and efficiency. Replacing old, worn tires with new ones can greatly improve your car’s fuel economy.

When Was Your Last Oil Change?

Keeping up with regular oil changes is important not only for your engine’s health but also for its fuel efficiency. Over time, as oil gets dirty and degrades, the friction within the engine can increase. This can cause your engine to work harder, consuming more fuel. Monitor your oil levels regularly, and keep up with recommended oil change intervals to help your engine run smoothly and efficiently.

Do You Drive Aggressively?

One of the easiest ways to improve your car’s fuel economy is to change your driving habits. Quick acceleration and hard braking can significantly reduce your fuel efficiency. Therefore, aim for a smoother, more gradual acceleration and braking approach when on the road. By being conscious of your driving habits, you can save on fuel costs and be safer for you and everyone else on the road.


It can be frustrating when your car’s fuel efficiency starts to decline, but with some knowledge and proactive maintenance, you can help it regain some of its lost fuel economy. We hope our guide has helped you find out why your car’s fuel economy is getting worse and offered an applicable solution.

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