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

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, multimeter, compression tester, fuel injector cleaner.
• Disconnect the battery to ensure safety while working on electrical components.

2. Replace Spark Plug

• Remove the ignition coil from cylinder 1 using a socket wrench.
• Remove the spark plug using a spark plug socket and inspect it for wear or fouling.
• Replace with a new OEM or equivalent spark plug, torquing to the manufacturer's specification (typically around 13-15 lb-ft).
• Reinstall the ignition coil securely and reconnect any electrical connectors.

3. Test and Replace Ignition Coil (if necessary)

• Use a multimeter to check the resistance of the ignition coil.
• If the resistance is out of spec, replace the ignition coil for cylinder 1 with a new one.
• Reinstall the ignition coil and reconnect all electrical connections.

4. Clean or Replace Fuel Injector

• If the fuel injector is suspected to be faulty, remove the injector from cylinder 1.
• Clean the injector using a fuel injector cleaner or replace it with a new one if necessary.
• Reinstall the fuel injector and ensure all connections are tight and secure.

5. Perform Compression Test

• Insert the compression tester into the spark plug hole of cylinder 1.
• Crank the engine and record the compression reading. If it is below specifications (usually around 180 psi for a healthy engine), further investigation into internal engine issues may be required.