how to fix P0301 misfire code on my Toyota Tacoma N300 (2016-Present)

Solution

1. Preparation

• Gather all tools and parts needed.
• Disconnect the negative battery terminal to ensure safety during repairs.

2. Inspect and Replace Spark Plug

• Sub-steps:
  1. Remove the ignition coil from cylinder 1 by unbolting and disconnecting the electrical connector.
  2. Remove the spark plug using a spark plug socket and ratchet.
  3. Inspect the spark plug for wear, carbon buildup, or damage; replace if necessary.
  4. Install a new spark plug by hand tightening it first, then torque it to specification (typically 13-16 lb-ft).
  5. Reattach the ignition coil and connector.

3. Test and Replace Ignition Coil (if necessary)

• Sub-steps:
  1. Use a multimeter to check the resistance of the ignition coil (consult service manual for specs).
  2. If the resistance is outside the specified range, replace the ignition coil with a new one.
  3. Reconnect the ignition coil and ensure it's securely fastened.

4. Inspect and Replace Fuel Injector (if necessary)

• Sub-steps:
  1. Disconnect the fuel injector connector and remove the retaining clips.
  2. Pull the fuel injector out from the rail (ensure fuel pressure has been relieved prior).
  3. Check the injector for clogs or damage; if faulty, replace it with a new injector.
  4. Reinstall the new or cleaned injector and secure it with the clips.

5. Recheck for Vacuum Leaks

• Sub-steps:
  1. Start the engine and spray a small amount of brake cleaner or soapy water around the intake manifold and vacuum hoses.
  2. Listen for any changes in engine RPM, which indicates a vacuum leak. Repair any leaks found.

6. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal and use an OBD-II scanner to clear the P0301 code.
• Start the engine and ensure that the check engine light does not reappear.