how to fix P0301 misfire code in my Toyota Highlander Third Generation (2014-2019)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to avoid electrical shock.

2. Replace Spark Plug

1. Remove the ignition coil from cylinder 1:
   • Unscrew the mounting bolt using a socket set.
   • Gently pull the ignition coil out of the spark plug hole.
2. Remove the spark plug:
   • Use a spark plug socket and ratchet to unscrew the spark plug.
   • Inspect the old spark plug for wear or damage.
3. Install the new spark plug:
   • Apply anti-seize lubricant to the threads of the new spark plug.
   • Torque to manufacturer specifications (typically around 13-16 lb-ft).
4. Reinstall the ignition coil:
   • Insert the ignition coil back into the spark plug hole.
   • Secure it with the mounting bolt and reconnect the electrical connector.

3. Replace Ignition Coil (if necessary)

1. If the ignition coil was found faulty during diagnostics, replace it:
   • Remove the old ignition coil as explained above.
   • Install the new ignition coil and secure it.

4. Inspect and Clean Fuel Injector (if necessary)

1. If fuel delivery is suspected to be an issue:
   • Disconnect the fuel injector connector and remove the injector.
   • Clean the injector with a suitable cleaner or replace it if damaged.
   • Reinstall the injector and reconnect the connector.

5. Test for Vacuum Leaks

1. Inspect all hoses connected to the intake manifold for cracks or disconnections.
2. Use a smoke machine or carburetor cleaner to check for leaks in the intake manifold.