how to fix a P0301 misfire code on my Toyota Camry XV40 (2007-2011)?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to avoid electrical shorts.
• Ensure the vehicle is on a level surface with the parking brake engaged.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket, dielectric grease.
• Remove the engine cover if necessary.
• Disconnect the ignition coil connector from cylinder 1.
• Remove the ignition coil by unbolting it and pulling it out.
• Unscrew the spark plug using a spark plug socket.
• Inspect the spark plug for wear or fouling; replace with a new spark plug if necessary (OEM specifications: NGK or Denso).
• Apply a small amount of dielectric grease to the spark plug threads before installation.
• Torque the new spark plug to the manufacturer's specifications (typically around 13-15 lb-ft).

3. Inspect and Replace Ignition Coil

• Tools Required: Socket set, torque wrench.
• If the spark plug is in good condition, inspect the ignition coil.
• Replace the ignition coil if damaged or if the problem persists after replacing the spark plug.
• Install the new ignition coil and torque to specifications (usually about 8-10 lb-ft).
• Reconnect the ignition coil connector.

4. Inspect Fuel Injector

• Tools Required: Fuel injector cleaning kit (if cleaning), replacement injectors if necessary.
• Remove the fuel rail if injector replacement is needed.
• Clean the fuel injector using a cleaning kit or replace it if faulty.
• Reinstall the fuel rail and ensure all connections are secure.

5. Clear Codes and Test

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0301 code.
• Start the engine and monitor for any misfire symptoms.