What exactly do spark plugs do?
Here’s the short answer. Your engine is a combustion machine. Every time you turn the key (or press the start button), your spark plugs ignite a tiny explosion that powers your car. These small but mighty components create the spark that lights the air-fuel mixture in your engine’s cylinders.
Without properly functioning spark plugs, your engine can’t run efficiently. Or at all.
Over time, spark plugs wear down, become dirty, or fail altogether. That’s when problems start. And because spark plugs are often out of sight, they’re easy to forget. Until your engine starts hesitating, misfiring, or refusing to start.
Why Spark Plug Maintenance Matters More Than You Think
Your car’s engine can’t run without spark plugs. Maintain the spark plugs and your car will remain in better shape. Wouldn’t it be nice if they provided you with warning signs?
Here’s some good news: spark plug issues don’t usually happen overnight. They build up gradually. And if ignored, they can take a toll on your vehicle’s:
- Fuel efficiency: Worn plugs can reduce fuel economy by as much as 30%.
- Performance: Acceleration feels sluggish, and engine misfires become more common.
- Starting power: Especially during cold Denver mornings, a worn plug can make starting difficult.
- Emissions: Bad plugs = incomplete combustion = more pollutants in the air.
- Engine life: Faulty spark plugs can lead to unburned fuel, carbon buildup, and strain on your ignition system.
Maintaining your spark plugs means smoother driving, better fuel economy, and fewer surprise breakdowns.
How Often Should You Replace Spark Plugs?
That depends on your vehicle, driving habits, and the type of spark plugs installed.
- Copper spark plugs: Typically last 20,000 to 30,000 miles
- Platinum or iridium spark plugs: Can last up to 60,000 to 100,000 miles
But Denver’s driving conditions can wear them down faster:
- Stop-and-go traffic increases heat and wear
- Cold starts in winter put more strain on ignition
- Mountain driving adds stress on the engine under higher loads
That’s why we recommend checking your spark plugs at least every 30,000 miles, or sooner if you notice any of the symptoms below.
Signs Your Spark Plugs Need Maintenance or Replacement
Every once in a while, pay attention to your car’s actions. It will give you warning signs if your spark plugs may be due for service:
Hard Starts or Trouble Starting
If your engine cranks longer than usual or takes multiple tries to start, worn spark plugs might be failing to ignite the air-fuel mixture.
Poor Fuel Economy
You used to go longer between fill-ups, but now your gas mileage has dropped. That’s often a sign of incomplete combustion, thanks to degraded spark plugs.
Engine Misfires or Rough Idling
A misfire can feel like a sudden jolt or a brief loss of power. If your car idles roughly or shakes at a stop, that could be a worn or dirty spark plug.
Sluggish Acceleration
Do you press the gas and feel hesitation before your car responds? Spark plugs may not be firing properly under pressure.
Check Engine Light
Modern vehicles have sensors that detect misfires and ignition problems. A persistent check engine light could point to faulty plugs.
What Happens During a Spark Plug Service?
Spark plug service is about more than just yanking out old plugs and screwing in new ones. The right way means paying attention to the little things:
- Inspection: We visually inspect your plugs for damage, wear, or carbon buildup.
- Gap Check: Each plug has a specified gap distance for your engine. We use precision tools to ensure each new plug is gapped correctly.
- Replacement: We install plugs that meet or exceed manufacturer specs—copper, platinum, or iridium, depending on your engine.
- Torque: We use the correct torque settings to avoid over-tightening or stripping threads.
- Performance Test: After installation, we test engine performance to ensure everything runs smoothly.
If needed, we also inspect your ignition coils or wires. These can fail too and often show symptoms similar to worn plugs.
Spark Plug DIY? Or Let the Pros Handle It?
If you’re experienced under the hood, changing spark plugs might seem like a weekend project. But many modern vehicles make spark plug access difficult, especially for V6 or V8 engines where plugs sit deep in the engine bay.
Other issues we see when DIY goes wrong:
- Stripped threads from over-tightening
- Incorrectly gapped plugs causing misfires
- Broken plug tips left inside the cylinder
- Using the wrong type of plug for the engine
Unless you’ve got the tools, knowledge, and service manual on hand, it’s safer (and often cheaper) to let a certified mechanic handle it. Statistics show that up to 90 percent of all spark plug damage claims are due to improper torque. Letting a professional mechanic do the job ensures it’s done the right way the first time.
Preventive Maintenance Saves You Time and Money
There’s a reason we talk about preventive maintenance so much here on our blog and in our service center: It saves you money. Regular spark plug maintenance helps you avoid:
- Expensive engine repairs from unburned fuel buildup
- Catalytic converter damage from misfires
- Stress on ignition coils (which are more costly to replace)
- Breakdowns on cold winter mornings when your engine won’t start
And the best part? It’s one of the most affordable and effective services for keeping your car running strong.
Don’t Skip Spark Plug Maintenance
Spark plugs might be small, but they have a big job. They will wear out over time.
If your vehicle is starting slower, burning more gas, or just not driving the way it used to, it might be time for a spark plug inspection.
We’ll check your spark plugs, ignition system, and make sure your engine is firing on all cylinders. No upsells. No pressure. Just honest, reliable service from a team that treats you like family.
We’re family-owned, Denver-local, trusted for years. We’re proud of that.
Schedule your spark plug check today and keep your car running smooth, mile after mile.