Back to all

Mileage Headed Downhill? (What Causes Bad Fuel Economy?)

October 5, 2025

Name someone you know who enjoys spending a lot of money on gasoline.  Yeah, me neither. That’s because it costs quite a bit to keep fueling your vehicle.  

One way to save money on gas is to get good fuel economy, and most of today’s vehicles are designed to maximize your mileage.  But you might find you’re filling up more frequently than you used to and are wondering what can cause your fuel economy to tumble.  Here are a few possible reasons your mileage has been headed downhill.

A logical spot to start is in your fuel system.  You may have a faulty fuel injector or an old fuel filter clogged with debris.  Another problem might be oxygen sensors, which measure the air coming into your engine and the emissions going out. An illuminated Check Engine light may be a sign of trouble there. Plus, worn-out spark plugs can reduce your fuel economy. 

Under- inflated, or over-inflated, tires can also be a cause. Make sure they’re all at the same pressure.  When’s the last time you changed your engine air filter? One that’s clogged and dirty can rob you of better fuel economy. Another bandit is a dirty, leaky, or clogged exhaust system, so have it checked out by a pro.

Finally, how you drive can also mean wasted gasoline. Jackrabbit starts and speeding use more fuel than smoother acceleration.  And if you often sit there with your engine idling while you’re waiting somewhere, you’re throwing fuel away.  Just turn the ignition off.

Try out some of these fuel-conserving habits and they’ll pay off for you in the long-run.

Tuffy Tire & Auto Service Center Lockport
600 E 9th Street
Lockport, Illinois 60441
815-838-3700

More articles from Tuffy Lockport

Stop! And See Us (Brake Pad Replacement)

November 23, 2025

If youve ever driven a bicycle with hand brakes, youll probably understand how the brake pads on your vehicle work. Bicycle brakes use a system that squeezes the bike wheels rim with a pair of cushioned pads activated by your hand squeezing the hand brakes on your handlebars. The friction of tho... More

Don?t Meddle with the Pedal (Brake Caliper Replacement)

November 16, 2025

If you drive a newer vehicle, chances are it has disc brakes, and one of the components of that type of brake is called a brake caliper. The caliper allows the pressure from your foot on the brake pedal to eventually move brake pads against discs in your wheels, which then slow and stop your veh... More

Why is My Brake Pedal Hard to Push?

November 9, 2025

When you push on your brake pedal, you should find your vehicle easy to stop. But at some point, you might notice stopping takes much more pressure on the pedal than it used to. When it gets to that point it becomes a safety issue, and you should bring your vehicle in so we can track down whats... More