how to fix my Toyota Corolla E140 (2006-2013) with a P0301 misfire code

Solution

1. Preparation

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

2. Replace Spark Plug

• Sub-steps:
  1. Remove the ignition coil from cylinder one by unscrewing the retaining bolts and disconnecting the electrical connector.
  2. Unscrew the spark plug using a spark plug socket.
  3. Inspect the old spark plug for signs of wear (such as carbon buildup or damage).
  4. Install a new spark plug, ensuring it is gapped correctly (0.043 inches for a Corolla).
  5. Torque the spark plug to the manufacturer’s specification (typically 13 lb-ft).
  6. Reattach the ignition coil by reversing the removal steps.

3. Test Ignition Coil

• Sub-steps:
  1. Use a multimeter to measure the resistance of the ignition coil.
  2. Compare the readings to manufacturer specifications (typically 0.6-0.8 ohms for primary winding).
  3. If the ignition coil fails the test, replace it with a new one.
  4. Reconnect the electrical connector and secure the ignition coil.

4. Check Fuel Injector

• Sub-steps:
  1. Remove the fuel injector connector from cylinder one.
  2. Use a noid light to check for electrical signal to the injector while cranking the engine.
  3. If there is no signal, trace the wiring back to the ECM for faults.
  4. If the injector is clogged, remove it and clean it using an ultrasonic cleaner or replace it if necessary.

5. Reassemble and Reconnect

• Reconnect the negative terminal of the battery.
• Ensure all components are securely fastened and no tools are left in the engine bay.