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

Solution

1. Preparation

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

2. Replace Spark Plug

• Sub-steps:
  1. Remove the ignition coil from cylinder 1 by unscrewing the mounting bolt and carefully pulling it out.
  2. Remove the spark plug using a spark plug socket and ratchet.
  3. Inspect the old spark plug for signs of wear (e.g., carbon buildup, worn electrode).
  4. Install the new spark plug by hand to avoid cross-threading, then torque to the manufacturer’s specification (typically around 13-16 lb-ft).

3. Replace Ignition Coil (if necessary)

• Sub-steps:
  1. If the ignition coil appears faulty, replace it by removing the retaining bolts.
  2. Disconnect the electrical connector from the ignition coil.
  3. Install the new ignition coil, connecting the electrical plug securely.
  4. Reattach any retaining bolts and ensure they are tightened properly.

4. Test Fuel Injector

• Sub-steps:
  1. If fuel delivery is suspected to be an issue, remove the fuel injector from cylinder 1.
  2. Use a fuel injector tester to check for proper spray pattern and flow.
  3. Replace the injector if it is clogged or malfunctioning, ensuring proper seating and connection.

5. Reassemble and Reconnect

• Sub-steps:
  1. Reinstall any components removed during the repair process, including the ignition coil and air intake components.
  2. Reconnect the battery terminals.
  3. Clear the trouble codes using the OBD-II scanner.