why is my Toyota Highlander XU70 (2020-Present) engine misfiring

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool before starting work.

2. Replace Spark Plugs

• Tools Required: Spark plug socket, ratchet, torque wrench, anti-seize compound.
• Remove the ignition coils by unbolting them and disconnecting the electrical connectors.
• Use a spark plug socket to remove the old spark plugs. Inspect for wear.
• Apply anti-seize compound to the threads of the new spark plugs.
• Install the new spark plugs and torque to the manufacturer’s specifications (typically around 13-16 lb-ft).
• Reinstall the ignition coils.

3. Inspect and Replace Ignition Coils (if necessary)

• Tools Required: Ratchet, socket set.
• Visually inspect each ignition coil for cracks or damage.
• Replace any faulty ignition coils with new ones, ensuring they are securely fastened.

4. Check and Replace Fuel Injectors (if necessary)

• Tools Required: Fuel injector puller, ratchet, torque wrench.
• Disconnect the fuel line and electrical connectors from the fuel injectors.
• Remove the fuel rail and inspect the injectors for clogs or leaks.
• Replace any faulty fuel injectors and reassemble the fuel rail.

5. Test for Vacuum Leaks

• Tools Required: Smoke machine or carburetor cleaner.
• With the engine running, use a smoke machine to identify leaks around the intake manifold.
• If using carburetor cleaner, spray around the intake gaskets and listen for changes in engine RPM.
• Repair any identified leaks by replacing gaskets or hoses as needed.

6. Final Inspection

• Reconnect the negative battery terminal.
• Clear any stored error codes using the OBD-II scanner.