Your engine relies on a controlled spark to ignite fuel and keep things moving. That spark comes from a combination of spark plugs and ignition coils. These two parts work together in the background every time you start your car, and they continue working as long as the engine is running.
If either one starts to wear out or fails, you may begin to notice a rough idle, poor gas mileage, or sluggish acceleration. That’s because the spark isn’t happening as cleanly or consistently as it should. The longer these issues are ignored, the more they can affect performance and fuel economy.
What Spark Plugs Actually Do
Spark plugs sit inside each cylinder and are responsible for lighting the air-fuel mixture. This controlled explosion is what drives the pistons up and down. Every time it fires, your spark plug creates a tiny electrical arc across a gap between two metal tips. That arc is the moment of ignition.
These parts are built to handle extreme pressure and high heat. Over time, though, deposits can build up on the tip, or the gap can widen. When that happens, the spark gets weaker or may not occur at all. That’s when you start feeling hesitation or misfires while driving.
The Role of the Ignition Coil
Spark plugs don’t produce their own electricity. That’s the ignition coil’s job. A coil takes 12 volts from your car’s battery and transforms it into the 20,000 to 40,000 volts needed to jump the spark plug gap. Without that high voltage, there’s no spark and no ignition.
Some cars have one coil that sends voltage to all spark plugs. Others have a coil for each cylinder, often placed right on top of the spark plug. Coil-on-plug systems are common in modern vehicles and help improve reliability and performance. But like spark plugs, these coils can wear out or fail over time.
What Happens When They Go Bad
If a spark plug is worn or a coil starts to fail, the result is usually a misfire. That means the cylinder doesn’t ignite the fuel properly, which causes rough running and wasted fuel. The check engine light may come on, and you might feel a shake at idle or when accelerating.
In some cases, the car may hesitate when you press the gas or feel like it’s running on fewer cylinders than it should. These symptoms often get worse under load or in colder weather. Ignoring them for too long can lead to more serious problems like a damaged catalytic converter.
How to Spot Trouble Early
You don’t have to wait for your check engine light to know something’s off. Here are a few warning signs that your spark plugs or coils might need attention:
- Trouble starting the engine
- A drop in fuel economy
- Sluggish or jerky acceleration
- Engine shaking at idle
- Engine light staying on or flashing
These problems don’t always point to the ignition system, but they are a strong hint that something related to spark or timing isn’t working right.
How Often Should You Replace Them
Spark plugs usually last between 60,000 and 100,000 miles, depending on the type. Iridium plugs last longer than copper ones, but every vehicle is different. If your car is getting older or hasn’t had a tune-up in a while, it might be time to check them.
Ignition coils don’t wear at the same rate as plugs, but they can still fail over time due to heat, vibration, or oil leaks. If one coil goes bad, it’s a good idea to test the others too. Replacing a full set at once may save money on labor and prevent future breakdowns.
Why Timely Replacement Is Necessary
If a coil or plug is on its way out, your engine won’t be running at its best. The longer you drive with a weak ignition, the more fuel you waste and the more wear you place on other components. Over time, repeated misfires can damage the catalytic converter or cause more expensive repairs.
It’s a small job to replace plugs and coils, but it can make a big difference in how your engine sounds, feels, and performs. You’ll get better fuel economy, smoother acceleration, and fewer surprises on the road.
Keep Your Engine Running Smooth with Premier Automotive Service in Urbandale, IA
If your vehicle is misfiring, hesitating, or just overdue for service, bring it to Premier Automotive Service in Urbandale, IA. We’ll inspect your spark plugs, test your ignition coils, and help you avoid future engine problems. Whether your check engine light is on or your car simply isn’t running the way it used to, our technicians will get to the bottom of it.
Schedule your ignition system check today and keep your car running the way it should.