IMPROVE GAS MILEAGE

If you already own a car, there are several gas consumption factors which you can't control: engine size and design, vehicle weight and wind resistance, gasoline quality and formulation. There are, however, a few ways in which you are the master of your driving fate, so let's concentrate on those. All of the strategies boil down to two words: maintenance and driving habits.

Maintain optimum tire pressure
It sounds like a no-brainer, but when was the last time that you checked your tire pressure? It takes more effort for an engine to propel an under inflated tire than a properly inflated one--the engine uses more gas to move it along.

The trickiest part of checking your tire pressure is that you actually have to check it twice: once before the vehicle has been moved that day, and again when you're at a gas station with an air hose. The first reading is from a cold tire, and it's the accurate one, while the second is from a tire that has warmed up from rolling on the pavement. The second reading will be a bit higher than the first. Here's the routine:

• Get a good quality tire gauge, and measure the pressure in all four tires before you move the vehicle. You'll do this by removing the plastic caps on your valve stems and pressing the gauge firmly down over the metal threads on the end of the stem. You'll hear a little hiss as a bit of air escapes, but when you press the gauge firmly down and hold it there, the noise will stop and the gauge will register the tire pressure.

• Write down the measurement for each tire--this is your cold measurement. Tire companies specifications reflect cold tire pressures, and pressure is measured in PSI, or pounds per square inch.

• The auto manufacturer has specified tire pressures for both front and back tires. Look for these specs on the inside edge of the driver's door, on the inside of the glove compartment door, or in the owner's manual. Use these numbers, rather than the numbers printed on the outside of the tire, to find out how much pressure  should  be  in  the  tires.  
   (See Infiniti tire pressure specifications at Tire Problems)

• Tires lose pressure at different rates. If you measure tire pressure every few weeks or so, you'll get a better idea of how often adjustments are necessary. Don't try to go by the tires appearance, as modern radial tires often look under inflated when they're not.

   Overly inflated tires can wear unevenly, so don't try to over inflate them into balloons.

Keep your engine tuned properly 
Nowadays, most cars on the road have electronic ignitions that are simpler to maintain than they used to be, but there are still a few items that need attention. (See Infiniti  Maintenance schedule)

• The air filter should be replaced when you can't easily see light through it.

• The timing should be properly adjusted. 

• The spark plugs should be clean.

Keep your exhaust system in good shape. A hole in your muffler or along your exhaust pipe will reduce your gas mileage as well as making noise and a bad smell.

In general, the faster you go, the more gas you use. 
The defunct "Drive 55" campaign in the U.S.A. was not only a safety measure, it was also an energy conservation measure: cars use less gas at 55 mph  than at 65 mph). Leave ten minutes earlier than you planned to, and drive a little slower than you normally do. As a bonus, you'll have more reaction time and may keep yourself out of an accident.

• Heavy acceleration and hard braking greatly reduce gas mileage. Smooth acceleration from traffic lights and gradual braking at stop signs will help more than you might think. And if you're driving through a residential area, you'll make it a safer and more pleasant place for the folks who live there.

• Constant speeds, rather than speeding up and slowing down, help enormously. That's why highway gas mileage estimates are always higher than the estimates for around-town driving. If you can plan your route to avoid strings of traffic lights, stop signs or children's play areas, your gas mileage will definitely improve.

• In most cars, the air conditioner draws power from the engine, using a belt. Every time that you turn on the air conditioner, the engine has to use more gas to keep the car moving. Although opening the windows can also reduce your gas mileage by reducing the aerodynamic efficiency, it's still better than running the air conditioner.

• Overloading the car makes the engine work overly hard and consume extra gas. If you can split the luggage (or building supplies) between two vehicles, then do it. This doesn't mean, however, that you ought to take two cars when one car will suffice.

¹According to the U.S. Department of Energy, nearly four million gallons of gasoline could be saved nationwide each day for every one pound per square inch (PSI) of tire under-inflation, compared to the mileage if ALL vehicle tires were kept inflated to the manufacturer's recommended pressure.

²The U.S. Department of Energy estimates that for 145 million passenger vehicles idling five minutes per day, approximately four million gallons of gasoline are consumed without going anywhere.

³According to the U.S. Environmental Protection Agency and Oak Ridge National Laboratory, a vehicle loses about one percent in fuel economy for every one mile per hour above 55 m.p.h. that it is driven. A passenger car that averages 30 miles per gallon at 55 m.p.h. could typically get 28.5 m.p.g. at 60 m.p.h., 27 m.p.g. at 65 m.p.h. and 25.5 m.p.g. at 70 m.p.h. Remember, however, that for different speeds, the changes in fuel economy will vary by vehicle model.

⁴Each 100 pounds of needless weight will cost up to one-half mile per gallon, on the average.