how to fix the P0301 misfire code on my Toyota Highlander XU70 (2020-Present)?

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface with the engine off and cooled down.
• Disconnect the battery to avoid electrical shock.

2. Replace Spark Plug

1. Remove the engine cover (if equipped) using a socket set.
2. Locate the spark plug for cylinder 1.
3. Use a spark plug socket to remove the old spark plug carefully.
4. Inspect the old spark plug for signs of damage or wear.
5. Install the new spark plug and torque to the manufacturer’s specification (typically around 13-15 ft-lbs).
6. Reattach the ignition coil.

3. Test and Replace Ignition Coil (if necessary)

1. Disconnect the electrical connector from the ignition coil.
2. Remove the ignition coil from cylinder 1 using a socket set.
3. Test the ignition coil with a multimeter; it should show proper resistance (check service manual for specific values).
4. If it fails the test, install a new ignition coil and torque to specification.
5. Reconnect all electrical connectors.

4. Fuel Injector Inspection and Cleaning

1. Disconnect the fuel injector harness and remove the fuel rail (if applicable) to access the injector.
2. Inspect the injector for clogs or leaks.
3. If necessary, clean the injector using an appropriate injector cleaner or replace it.
4. Reinstall the fuel rail and ensure all connections are secure.

5. Check for Vacuum Leaks

1. Visually inspect all vacuum hoses connected to the intake manifold.
2. Use a smoke machine or carburetor cleaner to check for leaks around the intake manifold and gaskets.
3. Replace any damaged hoses or gaskets as needed.