Introduction

This guide shows how to replace the spark plugs in your 2018-2024 Toyota Camry equipped with the 2.5L 4-cylinder engine.

The spark plugs provide the means for an electrical spark to ignite the fuel-air mixture in your engine. Because they are precisely matched to your engine, using the correct plugs (with the correct overall size and "gap") is important for proper operation.

Failing, fouled, or incorrectly-gapped spark plugs can cause misfiring, increased emissions, poor fuel economy, and ignition‑related trouble codes.

Note: The engine should be warmed up fully, and then allowed to cool down for 1-2 hours before performing this replacement.

    • Check the owner’s manual to confirm the correct mileage or time interval for spark plug service.

    • Obtain four genuine Toyota iridium spark plugs and verify the factory identification mark on each tip.

    • Gather a 14 mm spark plug socket with a rubber insert, an 8 mm socket, a ratchet, and a torque wrench that reads 15 ft‑lbs and 66 in‑lbs.

    • Avoid aftermarket or counterfeit spark plugs to prevent driveability problems.

    • Work on a warm engine: drive the car, then let it cool one to two hours before removal.

    • Pull the plastic engine cover upward at its three retaining tabs and lift it off the engine.

    • Store the cover safely; it dampens direct‑injection pump noise and must be reinstalled.

    • Press the release tabs and unplug the four ignition‑coil connectors.

    • Remove the four 8 mm bolts that secure the coils to the plastic valve cover.

    • Lift each coil straight up, ensuring the rubber weather seal comes out with the coil.

    • The coils are identical, so their positions do not need to be noted.

    • Handle the three‑wire coils carefully; they differ from older four‑wire Toyota coils.

    • Use a 14 mm extra deep spark plug socket with a ratchet on the first plug and loosen it, then repeat for the remaining three plugs.

    • Use the socket’s rubber insert to lift each plug out of the well without damaging the electrode.

    • Work slowly to avoid stripping aluminum threads; never remove plugs on a hot or stone‑cold engine.

    • A normal plug shows a light whitish band, a clean center electrode, and dry threads.

    • Wet plugs after normal driving suggest fuel or oil contamination that requires diagnosis.

    • Factory plugs carry a stamped mark on the tip; missing marks indicate non‑genuine or previously replaced plugs.

    • Thread each new plug by hand until fully seated to prevent cross‑threading.

    • Do not apply anti‑seize, grease, or any compound to the threads.

    • Never adjust the iridium gap; replace any plug that appears incorrectly gapped.

    • Torque each spark plug to 15 ft‑lbs with a calibrated torque wrench.

    • Push each coil onto its plug, confirming the rubber weather seal is present and seated.

    • Install the four 8 mm bolts and tighten them to 66 in‑lbs (5.5 ft‑lbs); avoid exceeding 7 ft‑lbs to protect the plastic valve cover.

    • Reconnect the coil connectors, following the gray‑black‑gray‑black order on the harness.

    • Align the oil‑fill opening in the cover with the filler neck.

    • Wiggle the cover until the tabs align with their mounts, then press down until all three clips snap into place.

Conclusion

Start the engine and confirm a smooth idle with no warning lights. Listen for misfires, then ensure the engine cover is secure. Record the mileage of the service for future reference.

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