how to resolve the P0300 random misfire code on my Toyota RAV4 Fourth Generation (2013-2018)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shocks.

2. Inspect and Replace Spark Plugs

• Remove the ignition coils by unscrewing the bolts or clips holding them in place.
• Carefully pull out the coils and set them aside.
• Using a spark plug socket, remove the spark plugs from the cylinder head.
• Inspect the spark plugs for wear and replace them with new plugs if necessary (use OEM recommended plugs).
• Reinstall the spark plugs and torque them to the manufacturer’s specifications (typically around 13-15 lb-ft).
• Reattach the ignition coils, ensuring they are seated properly.

3. Check and Replace Ignition Coils

• Test each ignition coil using a multimeter to check for proper resistance according to specifications.
• Replace any faulty ignition coils with new ones (OEM recommended).
• Ensure the connections are secure and properly seated.

4. Verify Fuel Delivery

• Connect a fuel pressure gauge to the fuel rail’s test port and turn the ignition to the "ON" position without starting the engine to check fuel pressure.
• If the pressure is below specifications (typically around 43-50 psi), inspect the fuel pump and filter.
• Clean or replace clogged fuel injectors as necessary.

5. Inspect and Repair Vacuum Leaks

• Visually inspect all vacuum hoses for cracks or disconnections.
• Use a smoke machine or propane to detect vacuum leaks while the engine is running.
• Repair or replace any damaged hoses to ensure proper intake air flow.