how to fix P0300 misfire code in Toyota Corolla E170 (2013-2019)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety while working on the electrical system.
• Allow the engine to cool down if it has been running.

2. Replace Spark Plugs

• Remove the ignition coil covers if applicable.
• Use a spark plug socket to remove the old spark plugs.
• Inspect the threads and clean them with a wire brush if necessary.
• Install new spark plugs to the manufacturer's specified torque (typically around 13-15 ft-lb).
• Reattach the ignition coil covers.

3. Inspect and Replace Ignition Coils (if necessary)

• Disconnect the electrical connector from each ignition coil.
• Remove the bolts securing the coils and take them out.
• Test each ignition coil with a multimeter to check for proper resistance.
• Replace any faulty ignition coils with new ones.
• Reinstall the ignition coils and reconnect the electrical connectors.

4. Check and Repair Fuel System

• Connect a fuel pressure gauge to the fuel rail Schrader valve.
• Turn the ignition to the "ON" position (do not start the engine) to check fuel pressure; it should be within the manufacturer's specifications (usually around 40-50 psi).
• If pressure is low, consider replacing the fuel pump or fuel filter.
• Ensure that fuel injectors are clean; use a fuel injector cleaner if necessary.

5. Inspect for Vacuum Leaks

• Start the engine and listen for hissing sounds around the intake manifold and vacuum hoses.
• Use a smoke machine to detect any vacuum leaks if necessary.
• Repair or replace any damaged hoses or gaskets.