Top 10 Misconceptions About Fuel Economy Exposed

Published January 3, 2016 by Carlton Wolf

You can find tons of information on how to preserve and increase your car's fuel economy on the Internet. Some of this information may be true, but most of the time it's just false promises to get you to part with your hard earned money.

Some of the most common questions about fuel economy are, "are fuel additives really necessary to increase gas mileage or are they just bogus products that don't work?" "Should you let your car warm up, if so, how long?" One of the best ones is, "Should you replace an aging car because as the vehicle gets older the fuel economy tends to get worse.

The United States Environmental Protection Agency (EPA) exposes many of these fuel economy myths and more. The list below will help new and used car shoppers make better car buying decisions, understand the EPAs role, and know which vehicle to choose and when you should choose it.

Top 10 Misconceptions About Fuel Economy Exposed

1) Myth: Bolt on Devices and Fuel Additives Increase Fuel Economy

This is the most controversial area in the gas mileage subject and there always seems to be a surge of these products when gas is north of $3 a gallon. These gas additives and aftermarket devices claim to magically increase your fuel economy, but no matter what they claim, the Better Business Bureau and the Federal Trade Commission doesn't believe it and warn you to not believe what they say either.

NOTE: The Environmental Protection Agency will only sign off comprehensive full conversions that meet all the strict EPA certification guidelines.

2) Myth: A Smaller Car Gets Better Gas Mileage

Back in the day this used to be a true statement before the rise of newer technologies. The Mitsubishi Mirage is the most fuel-efficient non-hybrid on the market right now at 40 miles-per-gallon. The Toyota Prius c hybrid is at the top of the chart with 50 mpg.

However, many of the bigger cars are becoming more competitive. For example, the 2016 Chevy Malibu Hybrid is rated to get 47 MPG. It has a lot more room and is a lot safer than a subcompact vehicle. Almost half of the vehicles on the EPA's top 10 list is comprised of midsized, wagons or large cars, and most of them are hybrids.

3) Myth: Replacing Your Car's Air Filter Helps Fuel Economy

Although you should change you air filter out on a regular preventive maintenance basis, changing it doesn't necessarily mean it will increase your fuel economy. Modern fuel injected engines will compensate and reduce the fuel to the engine when it senses a dirty air filter.

This myth is still hanging on from the days of the carbureted engines of the past. Dirty air filters would adversely affect these types of engines.

You should still change out your air filter when it's dirty, it will improve power by allowing your engine to breathe easier and the air-fuel-mix may be increased also.

4) Myth: You Should Let Your Vehicle Warm Up for the Best Gas Mileage

This is another oldie-but-goody. Letting your vehicle warm up for long periods of time in the winter does nothing but benefit you personally. It doesn't save you any fuel, a car gets zero miles to the gallon if it's sitting still. Modern cars are designed to be ready to drive within seconds of starting them up.

Manufacturers do have a recommended optimal engine temperature to get the best gas mileage, but they also recommend you begin driving the vehicle gently and carefully after first starting it up and letting it warm up as you're continuing on your journey. They also state you should not rev-the-engine or apply any heavy loads until the temperature comes up to an acceptable operating range.

5) Myth: EPA Stickers Guarantee a Vehicle's Fuel Economy

There is no way to guarantee the exact gas mileage on any vehicle, some consumers will get more and some will get less than what's listed. To many variables come in to play when determining gas mileage, including the drivers personal habits.

Even on the EPA stickers you see on new cars you will find a disclaimer stating, "Actual results may vary for many reasons." The EPA fuel economy estimates provide consumers with a unbiased, uniform way of comparing the efficiency of related vehicles. The EPA attempts to test gas mileage on new cars in real-world driving conditions, their estimates are not perfect.

6) Myth: A Vehicle's Gas Mileage Will Decrease With Age

Should you replace your vehicle if its five years old or older because it's starting to get less gas mileage? The EPA says, you may want to only if you're wanting to purchase a more fuel-efficient vehicle. However, as far as your older vehicle is concerned, as long as you've properly maintained it, it shouldn't have dropped from any original specs.

The EPA says, as long as you maintain your vehicle, even if it's ten years old or older. It will not vary from its original fuel economy from when it was new.

7) Myth: The Federal Government Tests All Vehicles for Fuel Economy

Vehicles over 8,500 pounds are NOT subject to testing by federal law. Larger pickup trucks such as the Chevrolet and GMC 2500\3500, Dodge 2500\3500, and the Ford F250/350 all exceed the weight limits and are excluded from testing.

8) Myth: It Takes More Fuel to Start an Engine Than to Let it Idle

Idling a vehicle can use up to a half-gallon of fuel per hour with some engines, this ends up costing you a couple cents per minute over time. With advances in technology, newer engines are very efficient when starting, especially when they're already warmed up.

9) Myth: Premium Gas Gets Better Gas Mileage than Regular Fuel

The EPA says, "you'll probably experience no benefit from using premium fuels over regular gas." The only time you should use premium fuel is in the case of engine knock when running on regular. The extra octane does not improve fuel economy, If you're vehicle will run on regular fuel, just use regular fuel. All you're doing is costing yourself additional money.

10) Myth: Manual Transmissions get Better Gas Mileage Than Automatics

This may be true to a sense, a perfectly well-operated manual may provide great fuel economy. But, it comes down to how well it's being operated and with zero human error. Many manufacturer's have discontinued the stick shift transmission as an option altogether.

Advances in technology have allowed the automatic transmission to match and even eclipse the fuel economy of the manual transmissions. Advanced automatics such as the continuously variable transmission (CVT) are being used in hybrids and many conventional cars.

Competition Between Dealers Always Gets You the Best Price

When negotiating the price of a new or used car, it's important to know the dealer invoice price and what other people are paying for the same vehicle in your local area. Otherwise, you won't know what a good price is to pay for the vehicle.

I highly recommend using an online referral service such as CarClearanceDeals or Edmunds, their quotes will automatically include any discounts or cash-back incentives currently available.