Cheap ways to improve fuel economy

By Brian Klaubert

Suddenly people are interested in improved fuel economy again. It is no wonder, with gas prices approaching $2 per gallon.

Fortunately, three of the biggest factors affecting fuel economy cost little or nothing at all. Probably the most common deficiency that contributes to degraded fuel economy is tire pressure. Low tire pressure increases the rolling resistance of the vehicle and burns more gas. Low tire pressure also produces premature wear on your tires and degrades handling response.

We frequently see cars with tire pressure in the low 20 psi range. You should never inflate your tires above the rated pressure stamped on the side wall. Very few, if any, tires have a rating of less than 35 psi. Passenger cars will have a comfortable ride with improved fuel economy if set at 34-36 psi. Many SUV tires will have a pressure rating of 44 psi. Running this high of a pressure will cause a harsher ride than most people like. However, running a 44 psi tire at 38-40 psi will provide comfort, good economy, and extended wear life.

The next item of inspection is your engine’s air filter, or air cleaner. Most air filters cost between $10-$20 to replace. A dirty air filter restricts air flow and can cause the engine to run richer. Computerized fuel air control moderates this effect, but keeping a clean air filter is very inexpensive.

The item that has the biggest effect on fuel economy is your driving style and habits. Shooting off from a stop sign or traffic light uses more fuel than moderate acceleration. Tail gating other drivers results in lower fuel economy, shorter brake life, and higher stress levels for both you and the driver ahead of you.

One of my technicians chose to change his driving habits to improve fuel economy on his 40 mile daily commute. He was able to increase his average fuel economy from 19 mpg to 23 mpg. That is a 21% improvement. Fuel prices have increased about 30%, so he has offset most of that increase.

Another item that will make an improvement is switching to synthetic engine oil. This should produce a 4% increase in fuel economy. Not only will it improve fuel mileage, but will also reduce engine wear.

I must reluctantly dispel one common misconception. Changing your spark plugs will rarely improve your fuel economy. It is only when the plugs have worn to the point where the engine cannot maintain a smooth idle, that changing the spark plugs will improve fuel economy.

I also must strongly caution against putting “specialty” spark plugs in. There are magazines and some parts stores that promote exotic spark plugs. Frequently these exotic plugs make your engine run worse. Vehicle manufacturers have tuned the entire combustion and computer control process to the specific spark plug that came in the engine. When you replace spark plugs you should only use exactly the spark plug specified as original equipment for your car or truck.

Do not put a platinum plug in a non-platinum application, and don’t substitute a cheaper plug where platinum is standard. We have solved problems where an engine would barely run, just by replacing the “specialty” plugs or platinum plugs with the original equipment plug.

Brian Klaubert owns Christian Brothers Automotive, awarded “Gwinnett’s Favorite Auto Mechanic” for 2004, on Hwy 124 in Dacula.