how to fix P0300 misfire code in Toyota Camry Eighth Generation (2018-present)

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool if recently operated.

2. Inspect and Replace Spark Plugs

• Sub-steps:
  1. Remove the ignition coil covers if present.
  2. Unplug the ignition coils from the spark plugs.
  3. Using a spark plug socket, remove the spark plugs.
  4. Inspect the condition of the spark plugs; replace if worn or fouled.
  5. Install new spark plugs to the manufacturer's torque specification (usually around 13-20 lb-ft).
  6. Reconnect the ignition coils.

3. Test and Replace Ignition Coils

• Sub-steps:
  1. Use a multimeter to test each ignition coil’s resistance.
  2. If a coil is out of specification, remove it by unbolting and disconnecting the electrical connector.
  3. Install the new ignition coil and ensure it is seated properly.
  4. Reconnect the electrical connector.

4. Inspect and Clean Fuel Injectors

• Sub-steps:
  1. Remove the fuel rail assembly to access the fuel injectors.
  2. Inspect each injector for clogs; clean them using an appropriate fuel injector cleaner.
  3. If cleaning is ineffective, replace the faulty injectors by disconnecting the fuel line and electrical connectors.
  4. Reinstall the fuel rail and ensure all connections are secure.

5. Check for Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum lines for cracks or disconnections.
  2. Use a smoke machine or carburetor cleaner to detect leaks while the engine is running.
  3. Repair or replace any damaged vacuum lines as necessary.

6. Test Fuel Pressure

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail test port.
  2. Turn the ignition on (do not start the engine) and note the pressure reading.
  3. Compare the reading to the manufacturer's specification (usually around 40-50 psi).
  4. If pressure is low, check the fuel pump and fuel filter for issues.