how to fix P0300 misfire code on my Toyota Highlander Third Generation (2014-2019)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shock.
• Ensure the vehicle is on a level surface and the engine is cool.

2. Replace Spark Plugs

• Tools Required: Socket set, torque wrench, gap gauge.
• Remove the ignition coils by unscrewing the retaining bolts and disconnecting the electrical connectors.
• Remove the spark plugs using a socket wrench.
• Check the gap on the new spark plugs with a gap gauge and adjust if necessary.
• Install new spark plugs and torque to the manufacturer’s specifications (typically 13-15 ft-lbs).
• Reinstall the ignition coils and ensure connections are secure.

3. Inspect and Replace Ignition Coils (if necessary)

• If faulty ignition coils were identified during diagnostics, remove them by unscrewing the bolts.
• Disconnect the electrical connectors from the ignition coils.
• Install new ignition coils and reconnect the electrical connectors.
• Torque the coils to manufacturer specifications.

4. Inspect and Clean Fuel Injectors

• Tools Required: Fuel injector cleaner, cleaning kit.
• If fuel injectors are clogged, use a fuel injector cleaning kit to clean them according to the manufacturer's instructions.
• If cleaning does not resolve the issue, consider replacing the fuel injectors.

5. Check Vacuum Lines

• Inspect all vacuum lines for cracks or disconnections.
• Replace any damaged vacuum lines to ensure proper engine performance.