how to fix P0301 misfire code in 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 down before starting work.

2. Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket, dielectric grease.
• Remove the ignition coil by unbolting it and disconnecting the electrical connector.
• Remove the spark plug using the spark plug socket.
• Inspect the old spark plug; if it’s fouled or worn, replace it with a new one.
• Apply dielectric grease to the new spark plug threads and install it. Torque to manufacturer's specifications (usually around 13-15 lb-ft).

3. Inspect and Replace Ignition Coil

• Tools Required: Socket set.
• After removing the spark plug, inspect the ignition coil for cracks or damage.
• If faulty, replace the ignition coil with a new one. Install it by reversing the removal process, ensuring the connector is secure.

4. Test Fuel Injector

• Tools Required: Noid light or stethoscope.
• Disconnect the fuel injector connector from cylinder 1.
• Connect a noid light to the connector to check for signal; if no signal, trace wiring or replace the injector.
• If using a stethoscope, listen for operation while cranking the engine.

5. Check for Vacuum Leaks

• Tools Required: Smoke machine or carburetor cleaner.
• Inspect all vacuum hoses and the intake manifold for cracks or disconnections.
• Use a smoke machine to introduce smoke into the intake system and look for leaks, or spray carburetor cleaner around suspected areas and listen for RPM changes.