why does my Toyota Highlander Fourth Generation (2020-present) engine misfire

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is parked on a level surface and turned off.
• Disconnect the battery to prevent electrical shocks.

2. Inspect and Replace Spark Plugs

• Tools Required: Socket set, torque wrench, spark plug socket
• Remove the engine cover if necessary.
• Detach the ignition coil connectors.
• Remove the ignition coils using the socket set.
• Using a spark plug socket, remove the old spark plugs.
• Inspect the spark plugs for damage; replace if worn or fouled.
• Install new spark plugs, tightening to the manufacturer’s specified torque (typically around 13-15 ft-lbs).
• Reinstall the ignition coils and connectors.

3. Check and Replace Ignition Coils

• Tools Required: Socket set, torque wrench
• If misfire codes indicate faulty ignition coils, remove the old coils as per the previous step.
• Install new ignition coils, ensuring they are seated correctly.
• Torque the bolts to the manufacturer’s specifications (usually around 7.2 ft-lbs).

4. Fuel System Inspection

• Tools Required: Fuel pressure gauge
• Connect the fuel pressure gauge to the fuel rail.
• Start the engine and observe the pressure reading; it should meet manufacturer specifications.
• If the pressure is low, consider replacing the fuel filter or fuel pump as necessary.

5. Vacuum System Inspection

• Tools Required: Visual inspection tools
• Inspect all vacuum hoses for cracks, leaks, or disconnections.
• Replace any damaged vacuum hoses to prevent air leaks that could cause misfires.