When Should Spark Plugs Be Replaced?

Spark plugs are a serviceable, yet extremely important, part of your Toyota’s engine. They sit inside the cylinder head where they create the spark that ignites fuel — the combustion that enables your engine to run. Spark plugs that have outlived their time will cause misfires in your engine — robbing it of efficiency and performance. Here’s what you need to know about spark plug replacement.

Different Kinds Of Spark Plugs

There are several types of spark plugs available through Toyota for your vehicle. Here’s the breakdown of each:

U-Groove Toyota Spark Plugs

The name explains the design of this plug — it uses a U-shaped groove in the ground electrode. This u-groove traps the air/fuel mixture before the spark plug fires, making for a large spark, reducing fouling, and making for more efficient combustion.

Dual-Ground Electrode Toyota Spark Plugs

Available for select models, this design has several benefits:

  • Both electrodes have platinum to reduce wear and extend service life.
  • The raised design offers a strong spark, smoother idle, and maximizes performance.
  • Incorporated with the platinum material is also nickel and iridium — resulting in higher resistance to cracking.

Iridium Toyota Spark Plugs

These spark plugs have many benefits:

  • Smaller center means higher firing performance
  • Iridium has a 1200ºF higher melting point over platinum
  • Iridium plugs last up to 110,000 miles longer than conventional spark plugs

Recommended Replacement

Here’s a comprehensive table for service intervals of each vehicle type:

Plug service chart

Replacement Before Time

These recommend replacement intervals are nothing to live and die by — they are merely meant to offer a guide. However, if you’re having issues with your spark plugs, you should absolutely replace them before then. Here’s how you know if it’s time to change the plug:

Rough engine idle. When your engine is not under acceleration (idling), it should run smoothly and consistently — if the plugs aren’t performing correctly, it will shudder and hesitate.

Trouble starting the car. If you’re having trouble starting the car, you may suspect the battery or fuel system, but it could be the plugs. When the engine isn’t getting enough spark, it could prevent a smooth start — it can also drain the battery.

Engine misfires. This is the most obvious and common sign of bad plugs. When the cylinders aren’t firing properly, it’s almost always related to the plugs or wires.

Toyota OEM plugs

Worsened fuel economy. Deteriorated spark plugs will cause an increase in fuel consumption of up to 30%!

Sluggish acceleration. Poor acceleration is pretty obvious, worn spark plugs will cause your vehicle to struggle to get up to speed.

Should you experience any of these symptoms while operating your vehicle, it’s time for a service. Pulling the spark plugs will make it obvious if replacement is needed — damage on the plugs is usually very obvious.

When you’re ready to replace your spark plugs at the regular interval, or if they have become damaged, start your search here for high-quality Toyota replacement plugs.