how to fix P0300 misfire code on my Toyota RAV4 XA50 (2019-2024)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool before beginning work.

2. Inspect and Replace Spark Plugs

• Remove engine cover: Use a socket set to unbolt and lift off the engine cover.
• Remove spark plugs: Use a spark plug socket to carefully unscrew and remove each spark plug from the cylinder head.
• Inspect spark plugs: Check for wear, carbon buildup, or oil contamination. Replace any faulty spark plugs with OEM specifications (typically NGK or Denso).
• Install new spark plugs: Torque to manufacturer specifications (usually around 13-15 ft-lbs).

3. Inspect and Replace Ignition Coils

• Remove ignition coils: Disconnect the electrical connector from each ignition coil and remove the bolts securing them to the engine.
• Inspect ignition coils: Look for signs of damage or wear. Replace any defective coils with OEM parts.
• Reinstall ignition coils: Secure them back in place and reconnect the electrical connectors.

4. Check and Clean Fuel Injectors

• Remove fuel injectors: Disconnect the fuel rail by removing the bolts and carefully lift it out to access the injectors.
• Inspect injectors: Look for clogs or leaks. Clean or replace any malfunctioning injectors.
• Reinstall fuel rail: Ensure all seals are in good condition before reattaching the fuel rail to the engine.

5. Verify and Repair Vacuum Leaks

• Inspect vacuum lines: Look for cracked or loose hoses connected to the intake manifold and other components.
• Use smoke test: If necessary, use a smoke machine to identify hard-to-find leaks.
• Replace damaged hoses: Replace any faulty hoses or connections to restore proper vacuum.