why does my Toyota RAV4 Fourth Generation (2013-2018) have a check engine light with P0300 code

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, vacuum gauge, fuel pressure gauge, smoke machine (if necessary).
• Safety Warnings: Disconnect the battery before working on electrical systems. Allow the engine to cool before performing inspections.

2. Replace Spark Plugs

• Remove the engine cover if applicable.
• Use the socket set to remove the spark plug wires or ignition coil packs.
• Remove the old spark plugs with the appropriate spark plug socket.
• Inspect and clean the spark plug holes of debris.
• Install new spark plugs, ensuring they are gapped correctly. Torque to manufacturer's specifications (typically around 13-15 lb-ft).
• Reconnect the ignition coils or spark plug wires.

3. Test and Replace Ignition Coils (if necessary)

• Use a multimeter to test the resistance of each ignition coil according to the manufacturer's specifications.
• If a coil is faulty, remove it using the socket set and replace it with a new one.
• Ensure proper connection of the wiring harness.

4. Inspect and Clean Fuel Injectors

• Remove the fuel rail if necessary to access the injectors.
• Clean the injectors using a specialized fuel injector cleaning kit or replace them if they are damaged.
• Reinstall the fuel rail and ensure all connections are tight.

5. Check for Vacuum Leaks

• Visually inspect all vacuum hoses connected to the intake manifold.
• Use a smoke machine to detect any leaks in the intake system.
• Repair or replace any damaged hoses or gaskets.

6. Verify Fuel System Functionality

• Connect a fuel pressure gauge to the fuel rail and check the fuel pressure against specifications (typically between 30-50 psi).
• Replace the fuel filter if pressure is low or the pump is faulty.