how to fix the P0300 misfire code on my Toyota Corolla E140 (2006-2013)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plugs

• Remove the ignition coil cover (if applicable) using a socket set.
• Disconnect the ignition coils from the spark plugs.
• Remove the old spark plugs using a spark plug socket.
• Inspect the spark plug gap and replace with new plugs if the gap is out of specification.
• Torque the new spark plugs to the manufacturer's specification (typically around 13-15 ft-lbs).

3. Inspect and Test Ignition Coils

• Remove the ignition coils from each cylinder by unbolting them and gently lifting them out.
• Use a multimeter to measure the resistance of each coil (consult specifications for correct values).
• Replace any ignition coils that do not meet specifications.
• Reinstall and torque the ignition coils to the manufacturer’s specification (usually around 7-9 ft-lbs).

4. Check and Clean Fuel Injectors

• Disconnect the fuel injector connectors.
• Remove the fuel rail with injectors attached (ensure to relieve fuel pressure first).
• Inspect the fuel injectors for clogs or leaks.
• Clean any clogged injectors using a fuel injector cleaning kit or replace them if necessary.
• Reinstall the fuel rail and ensure all connections are secure.

5. Inspect Vacuum Lines

• Visually inspect all vacuum lines for cracks, breaks, or disconnections.
• Replace any damaged vacuum lines or reattach any disconnected lines.
• Consider spraying starter fluid around connections while the engine is running to check for RPM changes indicating a leak.