how to fix P0300 misfire code in Toyota Corolla E210 (2019-2024)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative terminal of the battery to ensure safety.
• Allow the engine to cool down before starting work.

2. Inspect and Replace Spark Plugs

• Remove the ignition coil covers (if applicable) using a socket set.
• Remove each spark plug using a spark plug socket and torque wrench.
• Inspect each spark plug for signs of wear or damage. Replace with OEM or equivalent plugs if necessary.
  • Torque to manufacturer specifications (typically around 13-15 lb-ft).
• Reinstall ignition coils and covers.

3. Test and Replace Ignition Coils

• Disconnect the harness from each ignition coil.
• Use a multimeter to check the resistance of each coil; compare results with manufacturer's specifications.
• Replace any faulty ignition coils with OEM parts.
• Reconnect the harnesses.

4. Inspect and Clean Fuel Injectors

• Remove the fuel rail (ensure you relieve fuel pressure first).
• Inspect fuel injectors for leaks or clogging.
• Clean injectors using a fuel injector cleaning kit or replace them if necessary.
• Reinstall the fuel rail and ensure all connections are secure.

5. Check Fuel Pressure

• Connect a fuel pressure gauge to the fuel rail test port.
• Start the engine and check the fuel pressure against manufacturer specifications (usually around 43-50 psi).
• If pressure is low, inspect the fuel pump and fuel filter for issues.

6. Vacuum Leak Test

• Use a smoke machine or carburetor cleaner to check for vacuum leaks around the intake manifold and vacuum hoses.
• Repair or replace any damaged hoses or gaskets found during inspection.