how to fix P0300 misfire code in Toyota Corolla E140 (2006-2013)

Solution

1. Preparation

• Gather tools and parts needed for repair.
• Disconnect the negative battery terminal to prevent electrical shock.
• Allow the engine to cool before starting work.

2. Replace Spark Plugs

• Remove the ignition coil cover if applicable.
• Using a socket wrench, remove the spark plug wires or ignition coils.
• Use a spark plug socket to remove the old spark plugs.
• Inspect the spark plugs for wear; install new spark plugs (make sure they are the correct type and gap them if necessary).
• Reinstall the ignition coils and reconnect the spark plug wires.

3. Inspect and Replace Ignition Coils (if necessary)

• If any ignition coils tested faulty during diagnostics, remove them by unscrewing the retaining bolts.
• Disconnect the electrical connector from the ignition coil.
• Install the new ignition coil, ensuring a secure fit and reconnecting the electrical connector.
• Repeat for any additional faulty coils.

4. Clean or Replace Fuel Injectors

• If fuel injectors are clogged, use a fuel injector cleaning kit to clean them.
• If cleaning does not resolve the issue, remove the fuel rail and replace the faulty fuel injectors with new ones.
• Ensure all O-rings are lubricated and seated correctly during installation.

5. Repair Vacuum Leaks

• Inspect all vacuum hoses and connections for signs of wear or damage.
• Replace any damaged hoses.
• If using a vacuum gauge, recheck the vacuum readings after repairs to ensure they are within normal range.