5 Gas Mileage Mistakes That is Costing You at The Pump

Gas prices are on the rise, making it crucial to save money at the pump wherever you can. One of the best ways to save money on gas, is to improve your fuel economy. In the task of improving fuel economy, sometimes avoiding simple mistakes alone could save you money at the pump. Here's 5 mistakes to avoid making mileage worse.

Gas Mileage Mistakes to Avoid

1. Using the Wrong Type of Oil

Knowing what kind of oil works best with your vehicle is key to improving engine performance. Engines today are built on extremely tight tolerances, which is why oils such as 10W30 and even 5W30 have become less popular to oils like 0W20 and 5W20. If an oil is too thick for engine tolerances, the oil pump, and thus the engine, will work harder to force that oil throughout the system and maintain pressure, so much so, that using the wrong weight of oil can rob 5-10% of the engines potential horsepower.

One of the age-old myths is that as an engine gets older, or more “tired”, or even in hotter climates, that you should “use a thicker oil”. Don’t fall for this myth, because it is absolutely not true. Stick to your OE recommended weight of oil, and do not deviate.

If you need help, AutoZone makes it easy to find the right engine oil for your vehicle.

2. Driving on Under-Inflated Wheels

Have you ever tried to move a wheelbarrow or pedal a bike on an under-inflated tire? It’s not easy, and it’s just as difficult for your engine to maintain a car’s speed under the same conditions without working harder. While most vehicles today have Tire Pressure Monitoring to indicate when a tire is low, many vehicles do not. Most vehicles on the road today use either 32 or 36PSI as a pressure-standard for inflation.

Make sure your tires are properly aired up and keep a tire pressure gauge in the car at all times to check during gas fill-ups!

3. Big Tires / Big Wheels

We know, you love the bigger tires or the awesome new 18 or 20” wheels you put on your car. We like them too! Unsprung weight, or the weight riding at the axles and below, have major impacts on acceleration, braking, and handling. The more unsprung weight you have, the more your engine has to work harder to keep it in motion.

Choose your wheel/tire package carefully to make sure you’re not adding significantly more weight than your original wheel and tire, or as a bonus with many high-performance wheels and tires, you may be reducing it. The chances are very likely though, especially with trucks, that you’re increasing it, and if you’re trying to save money on gas, you may have to decide if the wheel/tire package is worth it right now.

4. Not Using Cruise Control

Cruise control can set and keep a constant speed and engine RPM, which takes your foot out of the game and the constant “speed up, slow down” scenarios, which increase gas mileage. Use cruise control whenever you can!

5. Using the Wrong Octane Fuel

What is Octane and how does it affect my car’s performance? Octane ratings and its impact on the performance of your engine have been debated for years. All manufacturers have specific octane requirements for your vehicle’s engine. Using a higher-rated octane fuel in an engine that doesn’t require it is throwing your money away. There will be no gains in power and in some cases, the engine can perform worse. Likewise, having an engine with a turbocharger that requires 92 or 93 Octane and using 87 to save money can cause lost power and fuel economy, or worse yet, engine damage.

The best rule is to follow what your manufacturer says! With vehicles that allow use of Flex Fuel (E85) or other Ethanol variants, it’s good to weigh out the mileage you’re getting per gallon to understand if its more economical to run E85 or not. E85 is substantially cheaper than regular 87, but E85 produces a weaker combustion, less power, and because of it, substantially less miles per gallon. The less MPG’s may, however, be offset by the savings per gallon, you’ll just need to weight out each by simply dividing the miles per gallon by the cost. For example:

  • 87 Octane $3.89 a gallon / 17.5 miles per gallon = 22.2 cents per mile
  • E85 $3.35 a gallon / 14.4 miles per gallon = 23.2 cents per mile

In the above scenario, E85 costs more per gallon to use than 87 Octane does, but this may not be the case everywhere. Log your mileage with each and compare!

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Be sure to consult your owner’s manual, a repair guide, an AutoZoner at a store near you, or a licensed, professional mechanic for vehicle-specific repair information. Refer to the service manual for specific diagnostic, repair and tool information for your particular vehicle. Always chock your wheels prior to lifting a vehicle. Always disconnect the negative battery cable before servicing an electrical application on the vehicle to protect its electrical circuits in the event that a wire is accidentally pierced or grounded. Use caution when working with automotive batteries. Sulfuric acid is caustic and can burn clothing and skin or cause blindness. Always wear gloves and safety glasses and other personal protection equipment, and work in a well-ventilated area. Should electrolyte get on your body or clothing, neutralize it immediately with a solution of baking soda and water. Do not wear ties or loose clothing when working on your vehicle.

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