how to fix the P0300 misfire code in my Ford Mustang S650 (2024-Present)

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, compression tester, noid light.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery by removing the negative terminal to prevent electrical shorts.

2. Replace Spark Plugs

• Remove the engine cover (if equipped) to access the spark plugs.
• Use a socket wrench to remove the spark plugs one by one.
• Inspect the old plugs for signs of wear or fouling. Replace them with new plugs that match OEM specifications.
• Torque the new spark plugs to the manufacturer's specifications (typically around 13-16 lb-ft).

3. Inspect and Replace Ignition Coils

• Disconnect the electrical connector from each ignition coil.
• Remove the bolts securing the ignition coils using a socket wrench.
• Carefully pull out the ignition coils and inspect for cracks or carbon tracking.
• Replace any faulty ignition coils with new ones.
• Reinstall the ignition coils and reconnect the electrical connectors.

4. Check Fuel Injectors

• Use a noid light to check the injector pulse by connecting it to the injector connector.
• If the light does not flash, check the wiring and the engine control module (ECM).
• If the injectors are functioning but clogged, remove and clean using a fuel injector cleaning kit or replace them if necessary.

5. Vacuum Leak Inspection

• Visually inspect all vacuum lines connected to the intake manifold for cracks or disconnections.
• Use a smoke machine or carburetor cleaner while the engine is idling to identify leaks.
• Replace any damaged vacuum hoses.

6. Perform Compression Test

• Remove all spark plugs to ensure the engine can crank freely.
• Insert the compression tester into the spark plug holes and crank the engine.
• Record the compression readings for each cylinder. If any cylinder has significantly lower compression, further diagnosis may be needed (e.g., valve or head gasket issues).