Spark Plug Replacement: Signs, Costs, and What You Need to Know

When your engine misfires, sputters, or struggles to start, the culprit isn’t always the battery or fuel pump—it could be your spark plug, a small but critical component that ignites the air-fuel mixture in your engine’s cylinders. Also known as a ignition plug, it’s the heartbeat of your combustion engine. Even if your car runs fine, worn spark plugs silently steal fuel efficiency, power, and smoothness. Most manufacturers say spark plugs last 30,000 to 100,000 miles, but real-world conditions in India—dusty roads, stop-and-go traffic, and poor fuel quality—can cut that life in half.

That’s why knowing the spark plug lifespan, how long a spark plug typically lasts before losing effectiveness matters more than sticking to a calendar. A plug that’s been sitting for 80,000 miles might still look fine, but carbon buildup or electrode erosion can make it useless. And if you ignore the signs—rough idling, poor acceleration, or the check engine light blinking—you’re not just wasting gas. You’re risking damage to your ignition system, the network of wires, coils, and sensors that deliver the spark to the plugs. A failing ignition system can overload your coil packs, leading to expensive repairs.

Replacing spark plugs isn’t rocket science, but it’s not always easy either. On some cars, you can reach them in 30 minutes. On others, you need to remove the intake manifold just to get to the back plugs. The cost? Basic copper plugs run under ₹500 each, while platinum or iridium ones can hit ₹1,500+. Labor usually adds ₹800 to ₹2,000, depending on your car’s design. Skip the cheap, no-name brands—Indian roads are tough enough without adding unreliable parts.

You’ll find plenty of advice online about cleaning old plugs or extending their life, but the truth is simple: if your engine isn’t running right, and your plugs are older than 50,000 miles, it’s time to swap them. No hacks, no myths. Just clean, fresh sparks for better throttle response, smoother starts, and lower emissions. The posts below break down real cases—from the squeaky Honda City to the tired Maruti Swift—showing exactly what failed, what it cost, and how to avoid the same mistakes.