10 Reasons Why Your Car’s Fuel Average is Low

fueling petrol in a car

One of the most common problems for cars is poor mileage which may be due to a myriad of reasons, some more technical than others. It often results from things drivers take for granted. Here is a list of the factors that are the common causes of low mileage.Advertisement

Tire Pressure

A flat tire will take you nowhere, and tires with either low or high pressure will make a vehicle less fuel-efficient. Drivers should always check the pressure of the tires before going on the road, especially before a long journey. It is advisable for drivers to carry a pressure gauge or to get it checked at a tire shop.


It is important for the tire pressure to be at the optimum level recommended by the manufacturer. It is mentioned in the owner’s manual or on the sticker pasted on the driver’s side pillar.

Air Filter

Vehicles need air to function properly, and disruptions in the flow of air to the engine can lead to issues. A clogged-up air filter causes bad fuel economy as the engine pulls in more fuel to compensate for the lack of air to produce the same amount of power.

Therefore, the drivers should periodically check the air filters and ensure that they are in working condition. A filter’s life expectancy depends on the driving conditions. If you are drive in the countryside, the filter will last longer, but if you drive in cramped urban places where the amount of smoke and dust is high, the filter will need to be changed often.

You can perform a simple check yourself. Put the air filter against a source of light like the sun. The light should be able to pass through it. If the filter obstructs the light, it needs to be replaced.

Oxygen Sensor

The oxygen sensor measures how well the fuel burns by measuring the amount of oxygen leaving the exhaust. If it finds too much oxygen, it indicates a lean burn; and if it finds a low amount of oxygen, it is indicative of a rich burn.

A faulty oxygen sensor will read the fuel burn as ‘lean’, and more fuel will enter the combustion chamber. This can reduce the mileage of the vehicle by 20 percent. A faulty oxygen sensor will also switch on the check engine light in the instrument panel when you start the vehicle.

Poor or Defective Fuel Injectors

As the name implies, fuel injectors inject fuel into the combustion chamber. A defective fuel injector will spray fuel in an irregular pattern or can develop a leak that will affect the mileage.

If a fuel injector gets clogged or develops a leak, the ‘Check Engine’ icon lights up on the instrument panel. If you have a defective fuel injector, you should take your vehicle to a mechanic because a proper installation is paramount to proper functioning.

Spark Plugs

Spark plugs produce the spark of life for a vehicle. As the pistons within the engine compress air and fuel in the combustion chamber, the spark plug produces the required voltage to ignite the mixture and keep the engine running.

Like the other parts in a vehicle, spark plugs can develop a fault which can result in a misfire, meaning that the spark plug had failed to ignite the fuel.Advertisement

In the case of a misfire, the engine tries to pull more fuel into the other chambers to produce the required amount of power, which results in low mileage.

Engine Oil

Using the wrong engine oil can lower mileage by 12 percent. Drivers should check the owner’s manual or consult a professional on which engine oil to use.

Poor Fuel Quality

Just as poor quality parts affect the performance of a vehicle, poor quality fuel takes its toll on it as well. Therefore, drivers must ensure that the fuel stations that they go to provide good quality fuels.

Worn-Out Clutch

Although less common, a worn clutch may result in low mileage. It may cause the two plates to slip against each other, which results in the loss of overall power at the wheels, and the efficiency of the transmission will decrease. The vehicle will then draw more fuel to produce the required power, and this will lead to low mileage.

Over Loading

Every unit of weight added to a vehicle affects its mileage. This happens because the more the amount of weight added to the vehicle, the more power the engine has to generate in order to move forward.

Drivers must avoid overloading as it affects mileage and increases the wear and tear of the tires and brakes.Advertisement

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Poor Maintenance

Drivers who neglect the maintenance of their vehicles often get poor mileage in return. This is because a maintenance check involves a mechanic examining the condition of the spark plugs, the flue injectors, the condition of the engine oil, the air filter, various sensors, and the aforementioned elements. The mechanic will also replace a faulty part to ensure the optimal performance of the vehicle.

Drivers and car owners should prioritize checking these details themselves or take their vehicles for regular maintenance to a mechanic.

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