Spark plugs may be small, but they have a big impact on engine performance. They create the spark that ignites the air-fuel mixture, powering your vehicle. Over time, worn-out spark plugs can lead to rough idling, poor fuel efficiency, sluggish acceleration, and even difficulty starting your car. Replacing them at the right time can prevent engine problems and keep your vehicle running at its best.
What Do Spark Plugs Do
Each time you start your car, the spark plugs generate a high-voltage spark to ignite the fuel inside the combustion chamber. This controlled explosion powers the engine, creating the energy needed to move your car. A properly functioning spark plug ensures efficient fuel combustion, smooth engine performance, and optimal fuel economy.
Signs Your Spark Plugs Need to Be Replaced
While spark plugs can last anywhere from 30,000 to 100,000 miles, depending on the type and manufacturer recommendations, they don’t last forever. Here are some common signs that indicate it’s time for a replacement:
1. Difficulty Starting the Engine
If your car struggles to start or requires multiple attempts before turning over, worn-out spark plugs may be the culprit. Faulty spark plugs fail to generate a strong enough spark, making it harder for the engine to ignite the fuel properly.
2. Rough Idling and Engine Misfires
A healthy engine should run smoothly when idling. If you notice rough vibrations, shaking, or sputtering while at a stoplight, faulty spark plugs could be the cause. When spark plugs fail, they can misfire, leading to inconsistent combustion and rough engine operation.
3. Poor Acceleration and Engine Performance
When spark plugs wear out, they don’t ignite the fuel mixture as effectively, leading to sluggish acceleration and reduced power. If your car feels slow to respond when you press the gas pedal, new spark plugs may help restore its performance.
4. Decreased Fuel Efficiency
Faulty spark plugs can lead to incomplete combustion, causing the engine to burn more fuel than necessary. If you notice that you're refueling more often despite driving the same routes, worn spark plugs might be affecting your fuel economy.
5. Check Engine Light Is On
Modern vehicles have onboard diagnostics that can detect engine misfires and inefficient combustion. A bad spark plug may trigger the check engine light, alerting you to an issue that needs attention. If the light is on, a professional diagnostic scan can confirm if spark plugs are the problem.
6. Unusual Engine Noises
A popping, rattling, or knocking sound from the engine can indicate that spark plugs are misfiring or struggling to ignite the fuel properly. These sounds occur when the combustion process is interrupted, leading to uneven engine operation.
7. Strong Fuel Smell from the Exhaust
If unburned fuel exits through the exhaust, you may notice a strong gasoline smell coming from your tailpipe. This often happens when spark plugs aren’t igniting the fuel efficiently, causing excess fuel to pass through the system without being fully burned.
Types of Spark Plugs and Their Lifespan
Spark plugs come in different materials, which impact their longevity:
- Copper Spark Plugs – Typically last 30,000 miles and are common in older vehicles.
- Platinum Spark Plugs – Last 50,000 to 60,000 miles and offer better durability.
- Iridium Spark Plugs – Can last up to 100,000 miles and provide the best performance and longevity.
Checking your owner's manual for manufacturer recommendations is the best way to determine when to replace your spark plugs.
If your car is showing signs of worn spark plugs, don’t wait for the problem to get worse. The experts at Ming’s Auto Repair in Allston, MA, can inspect and replace your spark plugs to keep your engine running efficiently. Call or stop by today to schedule your service!