how to fix P0301 misfire code on my Toyota RAV4 XA50 (2019-2024)?

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative battery terminal to avoid electrical shorts.
• Allow the engine to cool down before proceeding.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, gap gauge.
• Remove the ignition coil from cylinder 1 by unscrewing the bolts and disconnecting the electrical connector.
• Remove the spark plug using a spark plug socket.
• Inspect the spark plug for wear or damage; replace if necessary. Ensure the new spark plug is gapped according to manufacturer specifications (typically around 0.043 inches for Toyota).
• Install the new spark plug and torque to the manufacturer’s specification (usually around 13-15 lb-ft).
• Reinstall the ignition coil and connect the electrical connector.

3. Check and Replace Ignition Coil

• If the spark plug inspection reveals no issues, test the ignition coil with a multimeter.
• Tools Required: Multimeter.
• If the ignition coil is faulty, disconnect it and remove it from the engine.
• Install a new ignition coil, ensuring it is securely fastened and the connector is attached.

4. Inspect and Clean Fuel Injector

• Tools Required: Fuel injector cleaner, noid light.
• Disconnect the fuel injector connector for cylinder 1.
• Use a noid light to check for proper electrical signal to the injector.
• If the injector is faulty, remove it using a suitable injector puller.
• Clean the injector with a fuel injector cleaner or replace it with a new one.
• Reinstall the injector, ensuring proper seating and connection.

5. Perform Compression Test

• If misfire persists, perform a compression test on cylinder 1.
• Tools Required: Compression gauge.
• Remove the spark plug and install the compression gauge into the spark plug hole.
• Crank the engine and read the compression value; it should meet the manufacturer's specifications (usually around 180 psi for most Toyota engines).
• If compression is low, further diagnostics may be required to check for internal engine issues (valve problems, head gasket failure).