how to fix P0300 misfire code on Toyota Corolla E210 (2019-2024)

Solution

1. Preparation

• Gather tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.

2. Replace Spark Plugs

• Tools Required: Socket set, torque wrench, spark plug socket, anti-seize compound.
• Remove the engine cover, if present.
• Disconnect the negative battery terminal.
• Remove the ignition coils by unscrewing them and carefully pulling them out.
• Use a spark plug socket to remove the old spark plugs.
• Check the gap on new spark plugs and adjust to manufacturer's specifications.
• Apply anti-seize compound to the threads of the new spark plugs and install them.
• Torque the spark plugs to the manufacturer’s specifications (typically around 13-15 ft-lbs).

3. Inspect and Replace Ignition Coils (If Necessary)

• Tools Required: Socket set, multimeter.
• Use a multimeter to test the resistance of the ignition coils.
• If a coil is faulty, remove it by unscrewing it and disconnecting the electrical connector.
• Install a new ignition coil and reconnect the electrical connector.

4. Fuel Injector Cleaning/Replacement

• Tools Required: Fuel injector cleaning kit or replacement injectors.
• If injectors are clogged, use a fuel injector cleaning kit to clean them while installed, or remove and replace them if they are damaged.
• Reconnect any fuel lines and ensure there are no leaks after servicing.

5. Check for Vacuum Leaks

• Tools Required: Smoke machine or carburetor cleaner.
• Use a smoke machine to look for leaks in the intake manifold and vacuum hoses.
• If using carburetor cleaner, spray around suspected areas while the engine is running; if RPM changes, a leak is present.
• Replace any damaged hoses or gaskets.

6. Measure Fuel Pressure

• Tools Required: Fuel pressure gauge.
• Connect the fuel pressure gauge to the fuel rail.
• Turn the ignition on (do not start the engine) and check the pressure; it should meet the manufacturer's specifications (typically around 50-60 psi).
• If pressure is low, inspect the fuel pump and filter for issues.