Spark plugs don’t get much attention, but your engine depends on them to start, idle, and run the way it should. When they begin to wear out, you might notice rough starts, misfires, or a drop in performance. They won’t last forever—and replacing them at the right time can help you avoid bigger problems later on.
So how long do spark plugs really last? Here’s what affects their lifespan, what signs to look for, and when it’s time for a replacement.
What Spark Plugs Do
Every time you turn the key or push the start button, your spark plugs go to work. They ignite the air and fuel mixture inside your engine's cylinders, powering the vehicle with controlled explosions—over and over again, thousands of times per minute. The better they do their job, the smoother and more efficient your engine runs.
A worn or dirty plug can’t deliver a consistent spark, and even small inconsistencies in ignition timing can impact how the engine runs. That’s why staying on top of spark plug health is more important than most people realize.
How Long Spark Plugs Last
There’s no one-size-fits-all answer when it comes to spark plug lifespan—it depends on the type of plug and how you drive. Here’s a general breakdown:
- Copper spark plugs: Usually last 20,000 to 30,000 miles. They’re affordable and conduct electricity well but wear out faster than other types.
- Platinum spark plugs: Last about 60,000 to 100,000 miles. They’re more durable and often used in newer vehicles.
- Iridium spark plugs: These are the longest-lasting—often good for 100,000 miles or more. They’re also more expensive but worth it for vehicles that require precise ignition control.
Check your owner’s manual for manufacturer recommendations, but keep in mind that driving habits, engine condition, and even the weather can affect how long your plugs really last.
Signs Your Spark Plugs Might Be Worn Out
If you’ve ever had your engine feel sluggish, hesitate when accelerating, or vibrate while idling, spark plugs could be part of the problem. Some signs are subtle at first, but they tend to get worse the longer you go without replacing them. Common symptoms include:
- Trouble starting the engine
- Rough idle or misfiring
- Poor acceleration or response
- Drop in fuel economy
- Check engine light (often with misfire codes)
You might not notice all of these at once. Sometimes, the first sign is just a change in how the car feels—like it's working harder than it used to.
What Happens If You Don’t Replace Them
If spark plugs are left in too long, they can start to break down—not just in performance, but physically. Electrodes wear out, gaps widen, and deposits build up. At a certain point, they may stop sparking altogether, leading to misfires, engine hesitation, or even damage to ignition coils and the catalytic converter.
In severe cases, old plugs can seize in the cylinder head, making removal difficult and more expensive. That’s why replacing them before they completely fail is always the better route.
Spark Plugs Replacement
When it’s time to replace your spark plugs, it’s also a good idea to check the condition of your ignition coils, plug wires (if your car uses them), and even the valve cover gasket if there’s oil near the plug wells. If you're having a shop like ours do the service, these components are part of a thorough inspection.
It’s also worth noting that all spark plugs should be replaced at the same time to keep engine balance and performance consistent across all cylinders.
How Maintenance Helps You Save
Replacing spark plugs may seem like just another maintenance task, but it pays off in better fuel economy, smoother driving, and fewer surprise repairs. If you’re someone who drives in stop-and-go traffic often, or if your engine has had performance issues in the past, replacing them a little earlier than recommended can be a smart move.
Think of it this way—spark plugs cost a lot less than fixing damage caused by a misfiring engine.
Future Auto Service – Spark Plug Replacement You Can Count On in Burbank, CA
At Future Auto Service in Burbank, CA, we check spark plugs as part of our diagnostic process and routine maintenance. If your car is running rough, getting worse gas mileage, or has hit a milestone in mileage, we can let you know whether it’s time for a new set. Don’t let a simple part cause bigger problems—schedule a service today and keep your engine firing on all cylinders.