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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery cable to prevent electrical shock.

2. Replace Spark Plug

1. Remove the ignition coil from cylinder 1:
   • Unscrew any retaining bolts and disconnect the electrical connector.
2. Remove the spark plug:
   • Use a spark plug socket to unscrew and extract the spark plug.
3. Install the new spark plug:
   • Apply anti-seize compound on the threads if recommended.
   • Torque to the manufacturer's specifications (typically around 13 ft-lbs for most spark plugs).
4. Reinstall the ignition coil:
   • Connect the electrical connector and secure with retaining bolts.

3. Inspect and Replace Ignition Coil (if necessary)

1. Remove the ignition coil from cylinder 1 (if not already done).
2. Install the new ignition coil:
   • Ensure it is properly seated and connect the electrical connector.
3. Repeat the process for other cylinders if indicated during diagnostics.

4. Test Fuel Injector (if necessary)

1. Disconnect the fuel injector connector.
2. Use a noid light to check for signal:
   • If no signal is present, further diagnose the wiring or ECM.
3. Replace the fuel injector if it does not operate correctly.