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

Solution

1. Preparation

• Gather tools and materials.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool down.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the ignition coil and spark plug from cylinder 1.
• Inspect the spark plug for wear or deposits; replace it if necessary.
• Torque the new spark plug to the manufacturer's specification (usually around 13-16 lb-ft).
• Reinstall the ignition coil.

3. Check and Replace Ignition Coil

• If the spark plug is in good condition, test the ignition coil using a multimeter.
• If the coil is faulty, disconnect the electrical connector and remove the coil.
• Install a new ignition coil, ensuring it is seated properly and reconnect the electrical connector.

4. Test Fuel Injector

• Using a noid light, connect it to the injector harness for cylinder 1 to verify injector pulse.
• If there is no signal, check the wiring and ECM.
• If the injector is faulty, disconnect it and remove it from the fuel rail.
• Replace with a new fuel injector, ensuring proper installation and sealing.

5. Compression Test

• Remove the spark plug and connect a compression gauge to the cylinder 1 spark plug hole.
• Crank the engine to record the compression reading.
• If the reading is below specifications (typically 180-200 psi), further investigation of engine internals is required.