How to Maintain or Improve Fuel Economy

Look at every new car and many used cars, and you’ll likely notice two things: the EPA Fuel Economy and Emissions label for new cars and “Fuel Sipper” or “Thrifty” for used cars. Even at home or on the job, fuel economy might be of some importance to you, whether refueling costs are sucking away at your paycheck or siphoning from your bottom line. Finally, anyone concerned about the environment might also be looking into fuel economy, because the less fuel you burn, the fewer emissions go into the atmosphere.

At first glance, the best way to improve your fuel economy might be to buy another car with better mpg, but that’s not always a possibility. Starting with the vehicles already in your fleet, whether it’s a fleet of one, two, or 100, follow these tips to get the best fuel economy possible.

After huffing up a flight of stairs fully-laden with groceries, you’ll likely appreciate that your vehicles work exactly the same way – they even “inhale” oxygen and “exhale” carbon dioxide. In other words, the more weight they’re carrying, the harder they’re working. Similarly, pushing against the wind also expends more energy than if the car can cut through the wind. In either case, the end result is the same – more energy requires more fuel, driving down your miles per gallon (MPG). To get the best MPGs your vehicle can, see where you can reduce weight and improve aerodynamics. If you don’t need to carry it, consider leaving it home.

• In the average automobile, every 100 pounds extra weight exacts a 1% MPG penalty. Smaller vehicles will experience bigger penalties than larger vehicles.
• Roof racks and cargo boxes, particularly roof-mounted boxes and duffels can really depress your fuel economy, even unloaded. At speeds under 40 mph, aerodynamic problems might cost 2%-8% of your base fuel economy. At highway speeds, 65 mph to 75 mph, the penalty bumps significantly, costing 6%-25% more. Rear-mounted cargo boxes aren’t quite as bad, maybe costing up to 5% at highway speed.

Vehicle condition has a huge impact on fuel economy. When the engine is running properly, it’s using fuel most efficiently and delivering power most efficiently. On the other hand, when things aren’t working right, whether or not the check engine light (CEL) is on, more fuel is being used to get the same result, costing you more to drive the same distance. To get the best MPG out of your ride, keep it in good shape .

• At your next engine oil change, consider a flush and the lightest synthetic your engine is designed for. If your engine is designed to run 5W-20, it’ll use more fuel forcing 10W-30 through it. Synthetic oils also run cleaner and longer than conventional oils, saving you money on maintenance.
• Tire pressure is a big problem in the United States, and the National Highway Traffic Safety Administration (NHTSA) estimates that nearly half of all American vehicles are running with at least one underinflated tire, which is why tire pressure monitoring systems (TPMS) were mandated starting in 2007. Besides being the leading cause of tire blowouts, insufficient tire pressure also increases rolling resistance and fuel consumption. The Environmental Protection Agency (EPA) estimates that each pound underinflation exacts a 0.2% fuel economy penalty. Check and adjust tire pressure every week or two to maximize fuel economy.
• Speaking of tires, another way to improve fuel economy, at least the next time your tires are worn and in need of replacement, is to consider low rolling-resistance (LRR) tires. Consumer Reports (CR) estimates the average driver could save $78 per year in refueling costs, which isn’t huge, but every little bit helps. As with all tire factors, the reduced rolling-resistance of an LRR tire comes with a trade-off, and some consumers may experience reduced traction and cornering performance.
• Finally, the CEL or any other engine monitoring or control problems can seriously impact your fuel economy. The EPA estimates that a faulty oxygen sensor, also called Lambda or Air-Fuel Ratio sensors, can impact fuel economy by as much as 40%! Have any CEL or running problems diagnosed and repaired as soon as possible to extract the highest MPG possible.

This might be the hardest thing to change, especially if you’ve been driving for years or decades, but our driving habits can be costing us more MPG than necessary.

• The most basic advice we can give here is to simply slow down, especially on the highway. While the interstate might be rated at 65 mph and “everyone” seems to be driving 75 mph or more, it’s also costing you more to drive so fast. EPA fuel economy estimates are calculated at a pokey 55 mph, costing you about 5 MPG for every 10 mph. Driving the speed limit not only saves you fuel, but is also significantly safer.
• Depending on where you drive, road and traffic conditions can range from calm to insane – failing to remain calm can not only be bad for your health, but also drain your fuel tank. In stop and go traffic, aggressive driving, such as jack-rabbit starts and aggressive lane-changing, followed by sudden stops and excessive idling, can increase fuel consumption by 10%-40%. On the highway, aggressive driving can cost you 15%-30% in reduced fuel economy. In addition to saving you money at the pump, you can reduce your blood pressure and prevent car crashes by maintaining a calm demeanor.

At the end of the day, your real-world fuel economy depends on several factors coming together in harmony, just like a good latte or the right wine. You can use the right oil and the right tires but cancel out their benefits by carrying too much weight or driving too fast. Learn to balance all of these and you can maximize your fuel economy no matter what you drive.