Ways to Improve Gas Mileage - Truth Or Myth?


ith the fluctuating price of gasoline these days, we are constantly looking for ways to improve our car’s mileage.  Over the years (after all, the issue of gas prices has been with us for quite some time!), many swear by ‘tips’ that improve gas mileage per gallon (MPG). Many have some truth to them but most are pure myth.  Here are some that we have found to be most widely-believed and what current research and testing has revealed:

Changing a Dirty Air Filter will Boost MPG –   Part-Truth / Part-Myth

This may have been true when most cars used carburetors. But today's computer-controlled, electronic fuel-injected systems easily adjust and correct for a little dirt in the filter to help maintain efficiency. A recent government study revealed that drivers gained NO improvement in mpg by replacing dirty filters with new ones.

Driving With the Air Conditioner Off Saves Fuel – Part-Truth / Part-Myth

Turning on the air conditioning does burn more gas, particularly at low speeds or in city driving conditions. But it is still considered a myth because as you approach highway speeds, the drag created by rolling down the windows rather than rolling them up and cranking the A/C cancels out the extra fuel used to power the compressor, which is actually less at higher speeds when the engine is already pumping out more revolutions per minute (RPMs).

Gas Additives Boost Fuel Economy – Pure Myth

Using these additives during a two-thousand-mile road test actually resulted in a one-mile per gallon DECREASE!  The Federal Trade Commission (FTC) and Environmental Protection Agency (EPA) agree with these results and agree most additives or any other purported fuel-saving product are a waste of time and money. 

Keeping The Motor Running While Idling Saves Gas – Pure Myth

This is pure myth. Again, fuel-injected vehicles start very efficiently, so it’s better to turn off the engine if you'll be idling for more than 30 seconds. But that doesn't mean it's a good idea to shut off your engine when you stuck in traffic. That can be dangerous and contribute to your starter wearing out prematurely. One exception to this is with the new hybrids that safely shut the engine down automatically whenever the car is stopped and switches over to battery power.

Premium Gas Improves MPG – Pure Myth

You should stay away from higher-octane fuels if you can. The extra cost will easily eat up any savings from minimal mileage gains you might see. Further, the reality is that all but some of the highest-end luxury and performance models actually run well on regular fuel. Check with your vehicle's manufacturer or a trusted mechanic to determine what makes the most sense for your ride.

Over-inflating Your Tires Improves Fuel Economy – Pure Myth

By all means, inflate your tires to the recommended pounds per square inch (PSI). But ignore anyone who tells you to go beyond that.  Theoretically, it makes sense that if low PSI means more rolling resistance, then more air in the tire would reduce resistance. In practice, this can be dangerous.  Over-inflated tires can degrade handling and braking and cause uneven tire wear, which can lead to an increased risk of blowouts. Stay within recommended PSI for your vehicles and try to avoid going above or below the ranges.

Fuel Efficiency Decreases as Your Car Ages – Pure Myth

This is a problem of perception because the EPA has determined that after an initial break-in period, MPG can actually increase over the first several years of ownership if the car is properly maintained. When these increases finally subside, some owners may perceive a decrease, but in reality, you may simply be achieving the EPA estimates for your vehicle when it was new. A well-maintained car can often hit the same MPG figures for decades.