why is my Toyota Corolla E140 (2006-2013) giving me a P0301 misfire code?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Replace Spark Plug

• Remove the ignition coil by unscrewing the mounting bolts and gently lifting it off.
• Remove the spark plug using a spark plug socket and ratchet.
• Inspect the spark plug for fouling, wear, or damage; replace with a new spark plug if necessary.
• Reinstall the spark plug and ignition coil, ensuring they are secured properly.

3. Test and Replace Ignition Coil (if needed)

• If the spark plug appears in good condition, test the ignition coil with a multimeter; check the primary and secondary resistance according to OEM specifications.
• If the coil is faulty, remove it and replace it with a new one, ensuring the connectors are clean and secure.

4. Inspect and Clean Fuel Injector

• Remove the fuel injector for cylinder 1 using the appropriate tools.
• Inspect the injector for clogs; clean with a fuel injector cleaner or replace if necessary.
• Reinstall the injector, ensuring all seals are intact to prevent leaks.

5. Final Assembly

• Reconnect the battery and ensure all connectors are secure.
• Start the engine and check for any check engine light illumination.