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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Ensure the engine is cool before proceeding.

2. Inspect and Replace Ignition Components

1. Remove Engine Cover (if applicable)
   • Use a socket set to remove any bolts securing the engine cover.
2. Inspect Spark Plugs
   • Disconnect the ignition coils from the spark plugs.
   • Remove spark plugs using a spark plug socket.
   • Check for signs of wear, oil fouling, or carbon build-up; replace if necessary.
3. Inspect Ignition Coils
   • Visually inspect ignition coils for cracks or damage.
   • Swap coils between cylinders to see if the misfire follows the coil to identify faulty components; replace any defective ignition coils.

3. Check Fuel System

1. Test Fuel Pressure
   • Attach a fuel pressure gauge to the fuel rail test port.
   • Turn the ignition key to the ON position without starting the engine and check pressure against manufacturer specifications (typically 40-50 psi).
   • If the pressure is low, check the fuel pump and filter for issues.
2. Replace Fuel Filter
   • If applicable, replace the fuel filter as a preventive step.

4. Inspect for Vacuum Leaks

1. Visual Inspection
   • Check all hoses and connections for cracks or disconnections.
2. Use Smoke Test
   • If available, perform a smoke test to identify any hidden vacuum leaks.

5. Perform Compression Test

1. Test Each Cylinder
   • Remove spark plugs.
   • Connect the compression gauge to the spark plug hole for each cylinder.
   • Crank the engine and record the compression readings. All cylinders should be within specifications (typically 180-200 psi).

6. Reassemble and Test

• Reinstall spark plugs, ignition coils, and engine cover.
• Reconnect the negative battery terminal.