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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool down before starting work.

2. Replace Spark Plug

• Remove the engine cover (if necessary) using a socket set.
• Remove the spark plug wire or coil pack connected to cylinder 1.
• Use a spark plug socket to remove the old spark plug.
• Inspect the old spark plug for signs of wear or fouling.
• Install a new spark plug, ensuring it is gapped correctly (typically 0.043 inches for Toyota).
• Torque the new spark plug to the manufacturer’s specification (usually around 13 lb-ft).

3. Replace Ignition Coil

• If the spark plug replacement does not resolve the issue, remove the ignition coil from cylinder 1.
• Disconnect the electrical connector from the ignition coil.
• Remove the mounting bolts using a socket set.
• Install the new ignition coil, securing it with the bolts and reconnecting the electrical connector.

4. Clean/Replace Fuel Injector

• If ignition components are functioning well, check the fuel injector for cylinder 1.
• Disconnect the fuel injector electrical connector and fuel line (use caution as fuel may spill).
• Remove the fuel injector using a socket set.
• Clean the injector using a fuel injector cleaner or replace it with a new one.
• Reinstall the fuel injector and reconnect the fuel line and electrical connector.

5. Reassemble and Final Checks

• Reconnect the battery terminal.
• Reinstall any engine covers that were removed.
• Start the engine and let it idle to check for smooth operation.