how to fix my Toyota Corolla E170 (2013-2019) with a P0300 misfire code

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to prevent any electrical shorts.
• Ensure you are working in a well-ventilated area.

2. Inspect and Replace Spark Plugs

• Sub-steps:
  • Remove the ignition coil covers if applicable.
  • Disconnect the electrical connectors from each ignition coil.
  • Remove the ignition coils using a socket set.
  • Remove the spark plugs using a spark plug socket.
  • Inspect the spark plugs for wear and replace them if necessary (recommended gap: 0.043 inches).
  • Install new spark plugs and secure them to the specified torque (typically 13-15 lb-ft).
  • Reinstall ignition coils and reconnect the electrical connectors.

3. Check and Replace Ignition Coils

• Sub-steps:
  • If spark plugs are fine, proceed to inspect ignition coils.
  • Test each ignition coil with a multimeter; check resistance values (typically 0.5-2.0 ohms for primary, 10-15 k-ohms for secondary).
  • If any ignition coil is out of spec, replace it with a new one.
  • Reinstall ignition coils and ensure they are seated properly.

4. Inspect Fuel Injectors

• Sub-steps:
  • Remove the fuel rail by disconnecting it from the fuel injectors.
  • Use a fuel pressure gauge to check for proper fuel pressure (should be around 50-60 psi).
  • Clean or replace clogged fuel injectors as necessary.
  • Reinstall the fuel rail and ensure proper sealing.

5. Check for Vacuum Leaks

• Sub-steps:
  • Inspect all vacuum lines for cracks or disconnections.
  • Use a smoke machine to detect any vacuum leaks around the intake manifold.
  • Replace any damaged lines or gaskets as needed.