2021 Toyota Tacoma Spark Plug Type & Gap

Quick Reference: 2021 Toyota Tacoma Spark Plugs

Why the Right Spark Plug Matters

Selecting the correct spark plug is crucial for your Tacoma's engine health, performance, and fuel efficiency. Modern engines are precision instruments, and the spark plug is a key component in the combustion process. Using the wrong plug can lead to misfires, poor fuel economy, increased emissions, and even engine damage.

• Heat Range: This is one of the most critical specifications. The heat range determines how quickly the plug dissipates heat from the combustion chamber. A plug that is too "hot" (dissipates heat too slowly) can overheat and cause pre-ignition or detonation. A plug that is too "cold" (dissipates heat too quickly) can develop carbon fouling, leading to misfires. The factory-specified Denso plugs are designed with the exact heat range your Tacoma's engine requires.

• Electrode Material: The 2021 Tacoma uses long-life Iridium spark plugs from the factory. Iridium is an extremely hard and dense precious metal, allowing for a very fine center electrode. This fine-wire design requires less voltage to create a spark, provides a more focused and consistent spark kernel, and is incredibly resistant to wear. While older vehicles often used copper or platinum plugs, Iridium offers the best combination of performance and longevity, which is why Toyota specifies a long 120,000-mile replacement interval.

How to Gap a Spark Plug

Spark plug gap is the distance between the center electrode and the ground electrode. This distance must be precise to ensure a strong, healthy spark. For the 2021 Tacoma, the specified gap is 0.031 inches (0.8 mm).

While factory Iridium plugs typically come pre-gapped, it's wise to verify the gap before installation. Shipping and handling can sometimes alter the setting.

1. Use the Right Tool: Use a wire-style or feeler gauge gapping tool. Avoid the cheap "coin-style" gap tools, as they can put pressure on the fragile iridium center electrode and damage it.
2. Check the Gap: Slide the 0.031" wire or blade between the electrodes. It should pass through with just a slight amount of drag. If it's too loose or too tight, it needs adjustment.
3. Adjust Carefully: To adjust the gap, gently bend the ground electrode (the strap that extends over the center). Never pry against or touch the center electrode. Use the leverage point on your gapping tool or a pair of needle-nose pliers to make tiny adjustments until the gap is correct.

Replacement Procedure Tips

Both the 2.7L and 3.5L engines in the Tacoma use a modern coil-on-plug ignition system, which simplifies the replacement process.

• Coil-on-Plug Removal: Each spark plug has its own ignition coil sitting directly on top of it, secured by a single 10mm bolt. Before starting, blow compressed air around the coil and spark plug tube to prevent debris from falling into the cylinder when the plug is removed. Disconnect the electrical connector, remove the bolt, and gently twist and pull the coil straight up to remove it.

• The Anti-Seize Debate: The use of anti-seize compound on spark plug threads is a topic of debate. Modern Denso plugs often feature a special trivalent plating that provides anti-corrosion and anti-seizing properties, making additional compound unnecessary. In fact, applying anti-seize can act as a lubricant, leading you to over-torque the spark plug, which can stretch the plug shell or damage the cylinder head threads. Most manufacturers, including Toyota and Denso, recommend installing new plugs dry (without anti-seize) to a specific torque value.

• Dielectric Grease: A small amount of dielectric grease applied to the inside of the spark plug boot (where it connects to the plug's porcelain top) is highly recommended. This grease prevents the boot from sticking to the plug over time, makes future removal easier, and helps seal out moisture that could cause a misfire.

Known Issues

Fortunately, the 2021 Toyota Tacoma and its engines (2TR-FE and 2GR-FKS) are not known for widespread or common issues related to spark plug replacement. Unlike the notorious Ford 3-valve engines with their two-piece spark plugs that could break in the head, or certain GM engines with sensitive ionization-sensing ignition coils, the Tacoma presents a straightforward and reliable design. By using the correct OEM-spec plugs and following the proper torque specifications, you can expect a trouble-free replacement.

Need plugs replaced? Find a shop on Repairius.