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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety.
• Allow the engine to cool down before working.

2. Replace Spark Plug

• Tools Required: Socket set, spark plug socket, torque wrench.
• Sub-steps:
  1. Remove the engine cover (if applicable) using the appropriate socket.
  2. Disconnect the ignition coil connector for cylinder 1.
  3. Remove the ignition coil by unscrewing it from the cylinder head.
  4. Use a spark plug socket to remove the old spark plug from cylinder 1.
  5. Inspect the new spark plug for proper gap and install it in cylinder 1.
  6. Torque the spark plug to the manufacturer’s specification (typically around 13-16 lb-ft).
  7. Reattach the ignition coil and connector.

3. Inspect and Replace Ignition Coil (if necessary)

• Tools Required: Socket set, multimeter (for testing).
• Sub-steps:
  1. Use a multimeter to test the resistance of the ignition coil. Check manufacturer specifications for acceptable resistance range.
  2. If the ignition coil is faulty, replace it with a new one by removing it from the cylinder head.
  3. Install the new ignition coil and reconnect the electrical connector.

4. Check Fuel Injector (if necessary)

• Tools Required: Fuel injector cleaner, socket set.
• Sub-steps:
  1. Disconnect the fuel injector connector for cylinder 1.
  2. Remove the fuel rail if necessary to access the injector.
  3. Inspect the fuel injector for clogs or damage. Clean or replace it as needed.
  4. Reinstall the fuel injector and reconnect the fuel rail.

5. Final Assembly

• Reinstall any components that were removed during the repair process (engine cover, etc.).
• Reconnect the battery.