how to diagnose engine misfire in Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

• Gather tools and parts needed for repairs.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool if it has been running.

2. Replace Spark Plugs

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the engine cover (if applicable) using appropriate tools.
• Disconnect ignition coil connectors and remove the coils using a socket.
• Unscrew and remove the old spark plugs using a spark plug socket.
• Inspect the spark plug gap and condition; replace with new plugs if worn or damaged.
• Torque the new spark plugs to manufacturer specifications (typically 13-15 ft-lbs).
• Reinstall ignition coils and reconnect connectors.

3. Replace Ignition Coils (if necessary)

• Tools Required: Socket set, torque wrench.
• Remove the ignition coils that were previously uninstalled.
• Install new ignition coils and ensure they are seated correctly.
• Torque the ignition coil bolts to manufacturer specifications.
• Reconnect the ignition coil connectors.

4. Check and Replace Fuel Injectors (if necessary)

• Tools Required: Fuel injector removal tool, socket set.
• Relieve fuel system pressure by removing the fuel pump fuse and running the engine until it stalls.
• Disconnect fuel lines and electrical connectors from the fuel injectors.
• Remove the old fuel injectors and replace them with new ones. Ensure proper sealing.
• Reconnect fuel lines and electrical connectors.

5. Clear Codes and Reassemble

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear any fault codes.
• Reassemble any components removed during the repair process, including the engine cover.