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

Solution

1. Preparation

• Gather necessary tools and replacement parts.
• Disconnect the battery to prevent electrical shock.
• Allow the engine to cool before starting work.

2. Inspect and Replace Spark Plugs

• Remove the ignition coil covers using a socket set.
• Disconnect the ignition coil connectors and remove the coils.
• Remove the spark plugs using a spark plug socket.
• Inspect spark plugs for carbon buildup and wear; replace if necessary with OEM parts.
• Torque new spark plugs to the manufacturer's specification (typically 13 lb-ft for Toyota).

3. Check and Replace Ignition Coils

• Inspect ignition coils visually for cracks or damage.
• Test each ignition coil with a multimeter to ensure proper resistance (typically between 0.4 to 2.0 ohms).
• Replace any faulty ignition coils with OEM replacements.

4. Inspect Fuel Injectors

• Remove the fuel rail according to the manufacturer’s instructions.
• Check for clogged or leaking fuel injectors.
• Clean injectors using a fuel injector cleaner or replace them if necessary.

5. Check for Vacuum Leaks

• Inspect all vacuum hoses and connections for cracks or disconnections.
• Use a smoke machine or propane torch (without ignition) to detect leaks around the intake manifold and vacuum lines.
• Repair or replace any damaged hoses or gaskets.

6. Verify MAF Sensor Functionality

• Disconnect the MAF sensor and clean it with MAF cleaner.
• Inspect the wiring and connectors for damage.
• If cleaning does not resolve the issue, replace the MAF sensor with an OEM part.