why does my Toyota Highlander Fourth Generation (2020-present) sound like it's misfiring

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface with the engine off and cool.
• Disconnect the battery to prevent electrical shocks.

2. Inspect and Replace Spark Plugs

• Remove the engine cover if applicable.
• Disconnect the ignition coils by unplugging the electrical connectors.
• Remove the ignition coils using a socket set.
• Use a spark plug socket to remove the spark plugs. Inspect them for wear or damage.
• If worn, replace spark plugs with OEM or high-quality aftermarket plugs. Ensure proper gap settings as per manufacturer specifications.
• Reinstall ignition coils and reconnect electrical connectors.

3. Check and Replace Ignition Coils

• If misfire codes point to specific cylinders, inspect the corresponding ignition coils.
• Remove the faulty ignition coils as described above.
• Replace with new ignition coils, ensuring they are seated correctly.
• Reconnect electrical connectors.

4. Test and Clean Fuel Injectors

• Use a fuel injector cleaning kit to clean the injectors if they are suspected to be clogged.
• If cleaning does not resolve the issue, replace defective fuel injectors by removing the fuel rail.
• Ensure to use new O-rings when reinstalling injectors.

5. Inspect for Vacuum Leaks

• Visually inspect hoses and gaskets for any cracks or disconnections.
• Use a smoke machine or carburetor cleaner to detect vacuum leaks around the intake manifold.
• Repair or replace any damaged components.

6. Verify Fuel Pressure

• Connect a fuel pressure gauge to the fuel rail.
• Turn the ignition to the "ON" position without starting the engine and check the pressure reading.
• If the pressure is below specifications, consider replacing the fuel pump or fuel filter.