Unlock the Secrets to Better Fuel Economy : Root Causes of Poor Fuel Economy and DIY Fixes


In the modern age of soaring gas prices and environmental concerns, fuel economy has moved to the forefront of many people’s minds. But what factors might be impacting your vehicle’s fuel efficiency, and what can you do to improve it?

The Importance of Fuel Economy

Fuel economy refers to the relationship between the distance traveled and the amount of fuel consumed by the vehicle. It’s not just about saving money at the pump, but it’s also crucial for reducing our carbon footprint and preserving the environment for future generations.

Factors Contributing to Poor Fuel Economy

Several factors can contribute to poor fuel economy, many of which are under your direct control.

Driving Habits

How you drive plays a major role in your vehicle’s fuel economy.

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Rapid Acceleration and Braking

Quickly stepping on the accelerator or the brake uses more fuel than gradually changing speed. Imagine it like running versus walking – it takes more energy to sprint, right?

Excessive Idling

Letting your car idle for extended periods also burns fuel. It’s similar to leaving a light on when you’re not in the room – it uses energy, but it’s not productive.

While the ranking might vary based on the vehicle’s make and model, below are some common codes that may affect fuel economy:

  1. P0171 or P0174 – These codes indicate a system too lean in Bank 1 or Bank 2, respectively. It suggests that the fuel/air ratio is too lean, meaning there’s too much air and not enough fuel. This condition could result in poor fuel efficiency.
  2. P0420 – Catalyst System Efficiency Below Threshold. This code signifies that the catalytic converter isn’t functioning as efficiently as it should, potentially due to a problem with the air/fuel mixture, leading to increased fuel consumption.
  3. P0300 – Random/Multiple Cylinder Misfire Detected. Misfires can lead to increased fuel consumption because not all the fuel is effectively used for combustion.
  4. P0401Exhaust Gas Recirculation Flow Insufficient Detected. This error code might lead to a rich fuel condition, which in turn decreases fuel economy.
  5. P0113 – Intake Air Temperature Sensor 1 Circuit High Input. The Intake Air Temperature (IAT) sensor helps the car’s computer calculate how much fuel to inject. A malfunctioning IAT sensor could lead to incorrect fuel/air mixture and thus lower fuel economy.
  6. P0128 – Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature). If the engine does not reach its operating temperature, it can run rich, thus decreasing fuel efficiency.
  7. P0442Evaporative Emission Control System Leak Detected (Small Leak). This might cause the vehicle to run at a sub-optimal condition and result in poor fuel economy.
Vehicle Maintenance

Keeping your car in good shape is another key to improving fuel economy.

Tire Pressure

Tire pressure that’s too low can decrease fuel efficiency because it takes more energy for the car to move.

Engine Tuning and Oil Change

A poorly tuned engine and infrequent oil changes can also contribute to poor fuel economy.

Load and Weight

The heavier your vehicle, the harder the engine has to work, resulting in higher fuel consumption.

The Impact of Poor Fuel Economy

Poor fuel economy not only affects your wallet but also contributes to air pollution and global warming, leaving a lasting impact on our planet.

DIY Fixes for Improving Fuel Economy

Luckily, there are simple steps you can take to improve your fuel economy.

Optimize Your Driving Habits

By adjusting your driving habits, such as avoiding rapid acceleration and braking, and reducing idle time, you can significantly improve fuel efficiency.

Keep up with Vehicle Maintenance
Regularly Check Tire Pressure

Maintaining correct tire pressure can improve gas mileage by up to 3%.

Tune-up Your Engine Regularly

Regular engine tune-ups and oil changes ensure that your vehicle runs at peak efficiency, reducing fuel consumption.

Minimize Load

Reducing the weight your vehicle carries, especially on routine trips, can make a big difference in your fuel economy.


Improving fuel economy is about more 

than saving money; it’s about reducing environmental impact and maintaining the health of your vehicle. By understanding the root causes of poor fuel economy and implementing these DIY fixes, you can contribute to a more sustainable future.


1. How much can I improve my fuel economy with these DIY fixes?

The degree of improvement can vary depending on the initial condition of your vehicle and your driving habits. However, it’s not uncommon to see a 5-20% improvement.

2. Does the type of fuel I use affect my vehicle’s fuel economy?

Yes, using the correct grade of fuel for your vehicle is crucial. Check your vehicle’s manual to find out the right type of fuel for your car.

3. How often should I check my tire pressure?

It’s best to check your tire pressure at least once a month and before long trips.

4. Can the type of oil I use in my car affect my fuel economy?

Yes, using the correct type and grade of oil recommended by your vehicle’s manufacturer can enhance the efficiency of your engine and improve fuel economy.

5. Is it more fuel-efficient to use air conditioning or to open the windows?

This depends on your speed. At higher speeds, open windows can create aerodynamic drag that can decrease fuel economy. In such cases, it may be more fuel-efficient to use air conditioning. However, at lower speeds, it might be better to open the windows and turn off the AC to save fuel.