With fuel prices being what they are, it’s always helpful to find ways to save money at the gas pump. Although the car you drive and your driving habits play a role, there could be some overlooked maintenance and repair items hurting your fuel economy. Here are 10 of the most common causes of poor gas mileage:

A dirty air filter

Engines depend on oxygen to burn fuel efficiently; if your air filter is dirty, your engine is essentially struggling to breathe—and it has to work much harder. Your gas mileage may not suffer much at first, but it will decrease over time. This is generally recommended every 12,000 to 15,000 miles, although it will vary based on the make and model of your vehicle. 

Failing oxygen sensors

Oxygen sensors are responsible for measuring the unburned oxygen in the exhaust; they then send this information to the vehicle’s electronic control unit (ECU), which determines the correct oxygen-to-fuel ratio for the engine. If the oxygen sensors are failing, they can decrease your gas mileage by as much as up to 20%. 

Incorrect tire pressure

Believe it or not, tire pressure can significantly affect your gas mileage—regardless of whether they’re under-inflated or over-inflated. It’s a good practice to check your tire pressure every month; you can find the correct tire pressure for your car listed on or near the driver’s side door panel. Make sure to inflate your tires to the recommended pressure, not the max pressure. 

Issues with the fuel system

Fuel system issues, like a clogged or dirty fuel filter, dirty fuel injectors, leaks or clogs in the fuel line, or a faulty fuel pump, can all affect a vehicle’s fuel economy. When the fuel system is clogged or dirty, less gas can make its way through the system, causing the engine to run less efficiently and decreased performance. The longer fuel system issues go on without repair, the worse the issue can get as the vehicle’s computer tries to make adjustments by using more fuel. 

Exhaust system issues

Many drivers don’t realize the exhaust system plays an important role in fuel economy. Exhaust leaks or problems with the muffler, manifolds, oxygen sensor, and catalytic converter can all contribute to a decrease in fuel economy. If you’ve noticed your gas mileage has gone down, it’s a good idea to get your exhaust system inspected. 

Faulty spark plugs

According to the National Institute for Automotive Service Excellence, faulty spark plugs can decrease fuel economy by up to 30%. When the spark plugs misfire or fail, they prevent the engine from getting the combustion it needs to burn fuel efficiently. 

Motor oil issues

If your motor oil is low, it prevents your engine from getting the lubrication it needs, which makes it work harder to provide power. Old or dirty oil will cause similar problems. Using the wrong oil weight can also affect lubrication in the engine. As poor lubrication can cause issues with overheating and excessive wear and tear on the engine’s internal parts, it’s important to have oil changes performed regularly. 

Additional Tips to Improve Your Gas Mileage

In addition to repair and maintenance issues your car might need, here are a few other things to consider if your gas mileage isn’t what you expect:

• Accelerate gradually and keep a steady speed while driving
• Use cruise control on the highway
• Whenever possible, coast to red lights and stop signs
• Avoid running your AC at full blast—find a comfortable temperature and keep it there
• Remove unnecessary items that could weigh your car down
• Avoid idling when your car is parked
• Combine your trips and plan out the most efficient route to take

Visit Dan’s Auto Center to Get Your Gas Mileage Back On Track

If your gas mileage has gone down without any changes to your driving habits, your car likely has a repair or maintenance issue that needs to be addressed. Although maintenance may seem unnecessary if your car has been driving well, keeping up with it will help your vehicle run more efficiently. Maintenance also allows us to spot minor issues that may be developing. If caught early, it may help you avoid a larger, more expensive repair in the future.  

Keep your vehicle running its best and get the most out of your fuel economy—schedule an appointment at Dan’s Auto Center today! Call us at (503) 635-8335 or request an appointment online. 

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