how to fix P0301 misfire code in my Toyota Highlander XU70 (2020-Present)?

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 if it has been running.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the ignition coil from cylinder 1 by unscrewing the mounting bolts and gently pulling it out.
• Use a spark plug socket to remove the spark plug from cylinder 1.
• Inspect the spark plug for signs of wear, carbon buildup, or damage.
• If the spark plug is faulty, replace it with a new spark plug with the correct specifications. Torque to manufacturer’s specifications (usually around 13-15 lb-ft).

3. Inspect and Replace Ignition Coil

• Tools Required: Socket set, multimeter (if testing).
• Visually inspect the ignition coil for cracks or corrosion.
• If necessary, test the ignition coil’s resistance with a multimeter (consult specifications for the correct values).
• If the coil is defective, replace it with a new ignition coil. Ensure it is seated properly and reattach the mounting bolts.

4. Test Fuel Injector

• Tools Required: Fuel injector cleaner, fuel pressure gauge.
• Disconnect the fuel injector connector for cylinder 1.
• Use a fuel pressure gauge to check if the injector is delivering the correct pressure.
• If the injector is clogged or not functioning, clean or replace it as needed.

5. Check for Vacuum Leaks

• Inspect vacuum hoses and the intake manifold for cracks or loose connections.
• Use a smoke machine or carburetor cleaner to detect leaks while the engine is idling.