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Save Motor Fuel

Fuel Economy Tips for Personal Vehicles

In the early months of 2012, closely following a rise in tensions with Iran, fuel prices in the U.S. began a steady rise. Motor fuel prices in Montana, while lower than the national average over this period, tracked this rising trend. 

Gasoline prices in Montana rose more than 6 cents in a single week.

Several websites specialize in surveying retail gasoline outlets for pricing information. Probably one of the best known is the Gas Buddy site, which offers a color coded map depicting prices by county. The local site is available at: The American Automobile Association (AAA) also offers a website where you can enter a zip code to find area gasoline prices:  

The following tips can help wring better fuel efficiency out of almost any
personal vehicle:

Tune-Up | TiresWeight | Fuel-Use Monitors | Fuel: Regular or Hi-Test? | Driving HabitsSlow Down! | MiscellaneousAlternatives |Sources


The Classic Tune-Up


Break out the owners manual and give it the once-over. A properly timed and tuned vehicle is absolutely essential to fuel efficiency. Today, newer cars electronically adjust engine timing and multi-port fuel injection has rendered carburetor tuning a lost art. Changing out fouled spark plugs is the last vestige of the classic tune-up. Have this done according to the maintenance schedule and clean or replace the air filter. These simple steps can improve mileage up to 14 percent, according to some sources.

Ask your service station attendant for engine oil appropriate to seasonal operating conditions. Precise selection of an energy conserving motor oil can offer a 1 to 2 percent mileage advantage, according to a federal fuel economy website.

Many newer engines perform well with synthetic oil, but don’t make the switch casually. High viscosity synthetics can leak past worn oil seals and rings and generally offer little mileage improvement for most engines. 

Kick the Tires

Check Tires

Or better yet, check the tire pressure. Under-inflated tires rob mileage and over-inflated tires affect handling. Either situation can be dangerous. If the task is too much, check your favorite auto parts store for screw-on indicator caps. A green indicator means tire pressure is okay, yellow is a warning and red signals a problem. Battery-operated LED models are also available. Cost for any of these indicators should be in the neighborhood of $50 for the four road tires. Some high-end newer vehicles have electronic sensors on each tire that warn the driver when pressure is improper. These are available after-market as well, but tend to be pricey.

Have you noticed that most new cars now feature 16-inch and even 17-inch wheels with very little actual tire area? These are low-rolling resistance energy efficient tires. Manufacturers specify them at least partially to boost mileage ratings. Similar quality replacement tires can be hard to find for older rigs, but ask anyway at your preferred tire shop. At any rate, always match a proper tire to your vehicle and avoid running deep tread snow tires in the summer. (Studded snow tires must be removed by law over the summer months.) Your owners manual, the sticker in the glove box, or the boilerplate on the driver’s side pillar recommend proper tire pressures and should be relied on over the specifications on the tire sidewall.

Remember that tire pressure changes with temperature: a ten-degree Fahrenheit drop in temperature reduces pressure by one pound (and vice versa). Proper tire inflation can offer up to 3 percent better mileage over soft tires.

Drop that Load

Lighten the load

Are you still carrying around winter tire chains and a bag of sand in the trunk? Weight matters, particularly in lighter cars, and less is better. According to one source, each 100-pounds of cargo costs about 2 percent in fuel economy. Remove roof-top cargo containers and so-called “rocket boxes” when not in active use. Even the better designed models cause fuel-draining drag. Stash the kayak, canoe or other toys off the top of your vehicle until the next expedition. Expect savings in the 1 to 2 percent range for smaller cars.

Fuel-Use Monitors

Some newer cars feature real-time fuel consumption readouts on the dash. Similar units are available as after-market devices that plug into the onboard diagnostic port (ODP) typically found on cars manufactured since the mid-1990s. (This is what the mechanic plugs the diagnostic instrument into when your “check engine” light comes on.) But you don’t need a mechanic to install these modules. Simply program the unit with information specific to your car (i.e., size of engine). The readout shows fuel use under the current operating condition. Units with a trip computer feature fuel cost, average mpg, gallons used, maximum and minimum speeds, etc. Ask at your auto parts store for products like the Scan Guage II  or CarChip from Davis Instruments, or search for similar models online. Fuel savings depend on improvements to your bad driving habits, but user reviews cite good results. Cost should run less than $275.    

Fuel: Regular or Ethyl?

Does your owners manual specify high octane fuel? Older cars that specify high octane probably require it for proper performance. So-called “hi-test” motor fuels of 1960 had octane ratings well above 95, and some engines of the day “pinged” without high-octane gas. Premium gas in Montana is usually in the low 90s these days. But new cars today electronically retard timing and decrease compression when lower octane fuel is encountered. The owners manual may simply “recommend” rather than “require” higher octane.  Engine ping upon hard acceleration is the time-honored guide that your fuel grade is too low. But many experts feel regular highway conditions are a sufficient guide. Low-octane fuel is considerably cheaper at the pump — economy may not improve noticeably, if at all. There is never reason to use fuels higher in octane than specified in the owners manuals.

Shop for lower priced fuel, but don’t go too far out of your way. Look online or in your local newspaper for pricing, then fuel up when you’re in the neighborhood. The Gas Buddy site is popular: The local site is available at: AAA also offers a website where you can enter a zip code to find area gasoline prices:  

Driving Habits

Personal driving habits are a huge variable in fuel use. Two people driving the same model cars over similar terrain the same day can turn in widely different mileage. At least one mileage testing survey found the most significant savings are earned through good driving habits — up to 37 percent for drivers who reform from the worst behaviors. Here’s a few pointers.

Whoa Down!

Wind resistance becomes a considerable factor at speeds above 40 mph. You’ve known this since age four when you first stuck a hand outside the window of a moving car. Feathering your hand into the wind represents an aerodynamic ideal. Holding it flat against the wind represents the reality of most cars as they fly like bricks down the highway. The simple fact is most vehicles deliver optimal mileage at highway speeds well under 75 mph. Slowing down is a simple and significant measure that saves fuel. Savings vary from 7 percent to 23 percent, depending on type of car.

Yes, there probably is a car out there with a perfect aerodynamic profile and optimal weight-to-horsepower ratio that delivers its best highway mileage at 75 mph. You probably don’t own that car. According to one source, each 5 mph you drive over 60 mph is like paying an additional 24 cents per gallon for gas.

Some people argue that their time is more valuable than any potential fuel savings. And there’s always the isolated instance where you just have to rush off to a.) the church, b.) the emergency room, or c.) your own funeral. Really, though, unless you’re presiding over these functions, what’s the big hurry? An increasing number of major transportation companies have retrofitted their diesel trucks with accelerator governors that prevent drivers from attaining speeds much over 65 mph. These companies have weighed lost time and extra wages against fuel savings, too, and slowing down wins out.


Do you sometimes choose a washboard, gravel-road shortcut over a paved stretch of highway? Pavement can save up to 30 percent in fuel use over rough dirt roads.

Stay on highway roads

Gang up trips and errands and select the most efficient car from the menagerie parked around your house. After determining that a trip is actually necessary, try to avoid high-traffic time periods. City traffic lights are timed to speed limits and are best negotiated during off-peak intervals. If you’re braking a lot, you’re also accelerating a lot — that’s bad for fuel economy, particularly when coming to and from full standstill.

Electronic ignitions start up efficiently, which renders most instances of engine idling a patent waste of gas. Even winter warm ups shouldn’t last longer than a minute for newer cars. Remember, at idle you’re getting zero miles per gallon.

Got a manual transmission? Get through the gears quickly and avoid gearing down before stops. Negotiate hills, don’t attack them. Take the long view and plan a couple of blocks ahead of yourself in city driving.

Air conditioning takes energy — save it for highway speeds whenever you can. Roll up the windows and close down the sunroof when you run it. Set the cruise control if you have it for level, open-road highway travel. Wax your car — it improves airplane performance, why not cars?


Don’t even consider coasting down hills to save fuel. “Georgia overdrive” is a dangerous and illegal practice. But you can rediscover the joys of walking, bicycling, and the adventures that have always surrounded letting a perfect stranger into your car. While hitchhiking may have been cool thirty years ago, the trend today is toward “ride sharing.” Online posting sites (such as Craig’s List) offer ride sharing ads with an opportunity to screen potential travel companions. If public transportation is available, look into the routes and schedules. You might be surprised at what’s available since most services are looking to expand routes.

Keep heart. The perfect car is always either your first car — which exists only in the family photo album — or that longed-for new purchase — which is still on the engineer’s drawing board. If a new or used automobile purchase is within your budget, compare mileage offerings at the website:


Here’s several sites to turn to for gasoline prices in our state. This website uses data from the Oil Price Information Service (OPIS): Simply plug in your zip code for a listing of gasoline prices within that code. Here’s a color-coded gasoline price map from the comparison shopping site, GasBuddy: 

If you’re looking for the bigger picture of gasoline and fossil fuel, the Short Term Energy Outlook is a service of the U.S. Energy Information Administration (EIA) and offers explanations of current pricing with a look around the bend: Typically, a $10 per barrel spot-price increase translates into a 24 cent per gallon increase in retail gasoline, usually within two months or so. An even bigger picture is offered by this Department of Energy Publication: Transportation Energy Data Book: All the national statistics on all manner of transportation.

This commercial website offers a compendium of sources on fuel-efficient cars, gas saving products, and fuel efficiency myths.