FOULED or wrong or mismatched plugs make the vehicle use more fuel than necessary.
Here’s a look at what could make or break your car’s fuel efficiency, as revealed by acknowledged motoring experts Ferman Lao of Speedlab, Quezon Avenue; Olson Camacho of West Avenue, Quezon City; Deanna Sclar (author of “Auto Repair for Dummies”); and Dan and Judy Ramsey (who wrote “Teach Yourself Visually: Car Care Maintenance”).
Spark plugs
If your spark plugs are misfiring because they’re dirty or improperly gapped, the problem can cost you up to 25 percent in gas mileage, according to Sclar.
The role of this metal-and-ceramic part that uses high-voltage electricity to ignite the compressed fuel/air mixture in the cylinder is so important to fuel efficiency that Camacho listed it as his number one factor outside of driver habits.
The Ramseys recommend motorists to follow their car manufacturer’s advice on the proper maintenance and replacement schedule of their spark plugs. Many manufacturers recommend replacing spark plugs every one to two years (15,000 to 30,000 miles—roughly 24,000 to 48,000 km), though high-performance spark plugs can operate well for up to 100,000 miles (160,000 kilometers) before being replaced. In many cars you can do the replacements yourself if you have the basic tools.
Air filter
A clogged air filter, says Lao, can make fuel efficiencies spiral southwards. Camacho lists this as his number two culprit.
Sclar said a dirty air filter can cause you to lose one mile (1.6 km) per gallon (3.3 liters) while running at a speed of 50 mph (80 kph). By keeping your air filter clean, you get that extra mile back.
But it may not just be a matter of keeping it clean. The Ramseys remind motorists to make sure that the filter they install is the correct one for the model car and the engine. They advise motorists to compare filters offered at various prices. They can visually compare the products to determine which is of better quality. Also, put a label on the filter indicating the date when it was installed. That way, you know when it’s time to check it up.
Brakes
“Sticky” brakes, Lao describes, occurs when a brake is poorly adjusted. It may feel like it has that “drag” while the vehicle is in motion. Moving the wheel against a dragging brake takes more power, which means that your brake linings and the fuel in your tank don’t last as long, as further explained by Sclar.
“To check for dragging brakes, jack up each wheel and spin it. If a brake shoe or brake pad is dragging, you can feel it as you try to turn the wheel on the hub,” Sclar adds. Camacho lists sticky brakes as culprit number 3.
Wheel bearings
Bearings in need of replacement contribute to poor fuel economy, said Lao. If you hear a rumbling sound while driving or when spinning a jacked-up wheel, your wheel bearings may be worn and may need to be replaced, adds Sclar.
ACCESSORY belts can also cause a serious loss of running efficiency.
Sclar added that the wheel bearings are meant to prevent friction, and if they’re worn, it takes extra energy (read: Fuel) to turn the wheels.
Other ‘gas guzzlers’
Under inflated tires, worn underchassis components like tie rods and rack ends, shocks, bushings, poorly aligned tires, incorrect camber settings, and overcharged aircon systems—by themselves or in combination—can contribute to poor fuel economy, stressed Lao.
Sclar also reminds motorists that if the vehicle’s PCV [positive crankcase ventilation] valve isn’t functioning properly, your engine runs less efficiently, and you may be burning and polluting your oil and the air, as well.
Accessory belts
Sclar also said that if accessory belts that connect your fan, water pump, alternator, air conditioner and a variety of other devices are too loose or too tight, a serious loss of running efficiency can result.
Consult your owner’s manual for how often your vehicle needs a tune-up, and if it’s ovedue, have it done immediately.