how to fix P0301 misfire code in my Toyota Highlander Fourth Generation (2020-present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool completely before beginning work.

2. Inspect and Replace Spark Plug

1. Remove the engine cover (if applicable) using a socket set.
2. Disconnect the ignition coil connector on cylinder 1.
3. Remove the ignition coil using a socket wrench.
4. Use a spark plug socket to remove the spark plug.
5. Inspect the spark plug for wear; replace if necessary with a new spark plug that meets OEM specifications.
6. Install the new spark plug by hand, then torque it to the manufacturer's specifications (typically around 13 lb-ft).
7. Reinstall the ignition coil and reconnect the connector.

3. Check and Replace Ignition Coil

1. If the spark plug is in good condition, test the ignition coil using a multimeter.
2. If the ignition coil is faulty, remove it and replace it with a new OEM ignition coil.
3. Reconnect the ignition coil connector and ensure it is secured properly.

4. Inspect and Clean Fuel Injector

1. If the ignition coil and spark plug are functioning properly, inspect the fuel injector for cylinder 1.
2. Remove the fuel injector connector and fuel rail bolts, then carefully pull the fuel rail from the engine.
3. Remove the fuel injector and clean it using a fuel injector cleaning kit or replace it with a new injector if necessary.
4. Reinstall the injector and fuel rail, ensuring all seals are in place.

5. Final Checks

1. Reconnect the battery.
2. Start the engine and allow it to idle for a few minutes to ensure the misfire code does not reappear.