how to fix P0301 misfire code on my Toyota Corolla E140 (2006-2013)?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool before proceeding.

2. Inspect and Replace Spark Plug

• Sub-steps:
  1. Remove the engine cover (if applicable) to access the spark plugs.
  2. Use a socket wrench to remove the spark plug from cylinder 1.
  3. Inspect the spark plug for wear, carbon buildup, or damage. Replace if necessary.
  4. Install a new spark plug, ensuring it is gapped correctly to manufacturer specifications (typically 0.043 inches for Toyota).
  5. Torque the spark plug to the manufacturer's recommended specification (usually around 13 ft-lbs).

3. Check and Replace Ignition Coil

• Sub-steps:
  1. Disconnect the ignition coil connector and remove the mounting bolts using a socket wrench.
  2. Carefully pull the ignition coil from the spark plug tube.
  3. Inspect the coil for cracks or signs of wear. Replace if necessary.
  4. Install the new ignition coil, ensuring it is seated properly on the spark plug.
  5. Reconnect the ignition coil connector.

4. Test Fuel Injector

• Sub-steps:
  1. Remove the fuel injector connector from cylinder 1.
  2. Use a multimeter to test the resistance of the injector (should typically be around 12-16 ohms).
  3. If the injector is faulty, replace it with a new one.
  4. Reconnect the fuel injector connector after confirming functionality.

5. Reassemble and Final Checks

• Sub-steps:
  1. Reinstall any components removed to access the spark plug and ignition coil.
  2. Reconnect the battery.
  3. Start the engine and monitor for smooth operation.