how to diagnose a misfire in Toyota Highlander Fourth Generation (2020-present)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Ensure the vehicle is parked on a level surface with the engine off and cool.
• Disconnect the negative battery terminal to prevent electrical shocks.

2. Replace Spark Plugs

• Remove the engine cover (if applicable) using a socket set.
• Disconnect the ignition coil connectors and remove the ignition coils (if they are part of the misfiring cylinder).
• Use a spark plug socket to remove the old spark plugs.
• Check the gap on the new spark plugs and adjust as necessary (typically around 0.043 inches for the Highlander).
• Install new spark plugs and torque them to manufacturer specifications (usually around 13 lb-ft).

3. Replace Ignition Coils (if needed)

• If the ignition coils show signs of wear or if they are related to the misfire codes, install new coils.
• Position the new ignition coils in place and reconnect the electrical connectors.
• Ensure the coils are securely fastened.

4. Fuel Injector Cleaning or Replacement

• If fuel delivery issues are suspected, remove the fuel injectors using appropriate tools.
• Clean the injectors using a professional cleaning kit or replace them if they are clogged or faulty.
• Reinstall the injectors and ensure proper sealing.

5. Check for Vacuum Leaks

• Inspect all vacuum lines and the intake manifold for cracks or loose connections.
• Replace any damaged hoses or gaskets.