my Toyota Camry XV50 (2012-2017) with P0301 code is misfiring what's wrong

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, fuel pressure gauge, compression tester.
• Clear all DTCs from the ECU.
• Ensure the vehicle is parked on a flat surface, and the engine is cool. Disconnect the battery's negative terminal for safety.

2. Inspect Ignition Components

• Remove the engine cover if applicable.
• Spark Plug Replacement:
  • Remove the ignition coil connector and the coil bolt using a socket.
  • Carefully pull out the ignition coil.
  • Remove the spark plug using a spark plug socket.
  • Inspect the old spark plug for wear (replace if necessary).
  • Install a new spark plug (torque to manufacturer specifications, typically around 13 ft-lbs).
  • Reinstall the ignition coil and connector.

3. Check Fuel Injector

• Disconnect the fuel injector connector.
• Use a multimeter to check the resistance of the fuel injector; compare it with specifications (typically around 12-16 ohms).
• If the injector is faulty, replace it by removing the retaining clips and replacing it with a new injector.
• Reconnect the fuel injector connector.

4. Test Fuel Pressure

• Connect a fuel pressure gauge to the fuel rail's test port.
• Turn the ignition to the ON position (do not start) and check the pressure; it should typically be around 40-50 psi.
• If the pressure is low, inspect the fuel pump and filter for issues, replacing as necessary.

5. Perform Compression Test

• Remove all spark plugs and disable the ignition system to prevent starting.
• Insert the compression tester into cylinder 1.
• Crank the engine for several seconds and check the reading.
• A healthy cylinder should have a compression reading of approximately 150 psi or more. If low, further investigation into the engine's internal components may be required.

6. Inspect for Vacuum Leaks

• Visually inspect the intake manifold and vacuum hoses for cracks or loose connections.
• Use a smoke machine or spray a carb cleaner around the intake to identify leaks; listen for changes in engine RPM.