how to fix P0303 misfire on my Toyota RAV4 XA40 (2013-2018)

Solution

1. Preparation

• Gather the necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Replace Ignition Coil (if necessary)

• Tools Required: Socket set, torque wrench.
• Remove the engine cover (if applicable) to access the ignition coils.
• Unplug the electrical connector from the ignition coil for cylinder 3.
• Remove the ignition coil by unscrewing the mounting bolts and lifting it out.
• Install the new ignition coil into cylinder 3 and secure it with the bolts.
• Reconnect the electrical connector.

3. Replace Spark Plug (if necessary)

• Tools Required: Spark plug socket, torque wrench, gap gauge.
• Remove the ignition coil for cylinder 3 as previously described.
• Using a spark plug socket, unscrew the old spark plug from cylinder 3.
• Inspect the old spark plug for damage; ensure the new spark plug is gapped to the manufacturer's specifications.
• Install the new spark plug, tightening it to the manufacturer's torque specifications (typically 13-16 lb-ft).
• Reinstall the ignition coil.

4. Inspect and Clean/Replace Fuel Injector (if necessary)

• Tools Required: Fuel injector removal tool, fuel line disconnect tool.
• If the fuel injector is suspected to be faulty, remove it by disconnecting the fuel line and electrical connector.
• Use a fuel injector cleaning kit if cleaning is an option; otherwise, replace it with a new injector.
• Reinstall the fuel injector and reconnect all lines and electrical connectors.

5. Final Checks

• Reconnect the negative battery terminal.
• Start the engine and allow it to reach operating temperature.
• Observe for any engine misfires or check engine light.