Bad Gas Mileage? Your Spark Plugs Might Be the Culprit
by AutoExpert | 17 June, 2025
So your car's been hitting the gas station way more often lately, and you're wondering what the hell is going on. Before you start cursing out oil companies, there's actually a pretty simple explanation that most people never think about.
Those tiny spark plugs buried in your engine? Yeah, they might be the problem. When they get old and gunked up, your car basically starts chugging fuel like a drunk college kid with a beer bong. We're talking 30% worse gas mileage, which adds up fast when you're already paying through the nose at the pump.

Here's the kicker - nobody ever thinks about spark plugs until their car completely craps out. They're not exactly front and center like your tires or windshield wipers. Most mechanics say replace them every 80,000 miles or so, but let's be real, who actually keeps track of that stuff?
Your Car's Cry for Help
When spark plugs start dying, your car gets pretty dramatic about it. It'll make weird knocking sounds like someone's hammering under the hood. Sometimes it acts like a moody teenager and refuses to start in the morning. Or it'll feel sluggish when you're trying to merge onto the highway, which is always fun.
The sneaky part is the gas mileage thing. You don't wake up one day and suddenly your car needs twice as much gas. It creeps up on you over months, and most people just figure that's life with an older car.

Actually Worth Fixing
Getting new spark plugs isn't just mechanic BS - it actually works. Your car will stop being such a gas hog, start easier when it's cold outside, and run way smoother overall.

It's pretty basic when you think about it. Fresh spark plugs = better explosion in the engine = less wasted fuel. Old, crappy spark plugs = weak explosion = your engine working overtime to get the same power. Simple math that actually shows up in your wallet.