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

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative terminal of the battery to ensure safety.

2. Inspect and Replace Spark Plugs

• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Disconnect ignition coils from the spark plugs.
  3. Remove spark plugs using a socket set.
  4. Inspect plugs for signs of wear or fouling; replace if necessary (use OEM or equivalent).
  5. Gap new plugs according to manufacturer specifications before installation.
  6. Reinstall spark plugs and reconnect ignition coils.

3. Check and Replace Ignition Coils

• Sub-steps:
  1. Remove ignition coils from the engine.
  2. Test each coil using a multimeter (typically 0.4 - 0.6 ohms for primary resistance).
  3. Replace any faulty coils with OEM parts.
  4. Reinstall all coils securely.

4. Inspect and Clean Fuel Injectors

• Sub-steps:
  1. Remove the fuel rail assembly (ensure to relieve fuel pressure prior).
  2. Remove fuel injectors from the rail.
  3. Inspect injectors for clogs; clean them using a fuel injector cleaning kit if necessary.
  4. Replace any damaged injectors with OEM parts.
  5. Reinstall fuel injectors and fuel rail.

5. Verify Fuel Pressure

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail Schrader valve.
  2. Turn the ignition on without starting the engine and check the pressure (should be within manufacturer specifications).
  3. If pressure is low, inspect the fuel pump and filter for issues. Replace as needed.

6. Check for Vacuum Leaks

• Sub-steps:
  1. Inspect all vacuum hoses for cracks or disconnections.
  2. Use a smoke test or carburetor cleaner to identify leaks while the engine is running.
  3. Repair or replace any damaged vacuum hoses.