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

Solution

1. Preparation

• Gather necessary tools and parts. Ensure you have an OBD-II scanner, socket set, torque wrench, fuel pressure gauge, and multimeter.
• Disconnect the battery. This prevents accidental electrical shorts while working on the vehicle.

2. Inspect and Replace Ignition Components

• Remove ignition coils:
  • Disconnect the electrical connectors from each ignition coil.
  • Remove the bolts securing the coils using a socket set.
  • Pull the ignition coils out gently.
• Inspect and replace spark plugs:
  • Remove spark plugs using a spark plug socket and ratchet.
  • Check for signs of wear, such as carbon buildup or electrode erosion.
  • Replace with OEM spark plugs, ensuring proper gap specifications (typically 0.043 inches for Toyota).

3. Check Fuel System

• Check fuel pressure:
  • Connect a fuel pressure gauge to the fuel rail.
  • Turn the ignition to the "ON" position (without starting) to check for pressure. It should match the specifications (typically around 43-50 psi).
• Inspect fuel injectors:
  • Remove and clean injectors using a suitable cleaning solution. Consider replacing them if they show signs of clogging or damage.

4. Inspect Air Intake and Vacuum Leaks

• Check air intake:
  • Inspect the air filter for clogs and replace if necessary.
  • Examine the intake manifold for leaks using a smoke machine or carburetor cleaner.
• Repair any vacuum leaks found during inspection.

5. Mechanical Inspection

• Check timing components:
  • Remove the timing cover as necessary to inspect the timing belt/chain for wear.
  • Perform a compression test on each cylinder to ensure they are within manufacturer specifications.