how to fix P0300 misfire code on Ford Mustang S550 (2015-2023)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool completely before working.

2. Inspect and Replace Spark Plugs

• Remove the engine cover if applicable.
• Remove the ignition coil(s) by unscrewing the retaining bolts and disconnecting the electrical connectors.
• Remove the spark plugs using a spark plug socket and ratchet.
• Inspect the spark plugs for signs of wear; replace them with OEM or equivalent spark plugs if necessary.

3. Check and Replace Ignition Coils

• Test each ignition coil for resistance using a multimeter. Refer to the vehicle’s service manual for specific resistance values.
• If a coil is faulty, replace it with a new ignition coil following the same removal procedure as above.
• Reinstall the ignition coils and ensure they are securely connected.

4. Inspect Fuel Injectors

• Attach a fuel pressure gauge to the fuel rail to check for proper fuel pressure.
• Listen for the clicking sound of fuel injectors using a stethoscope or a similar tool; replace any that are not functioning.
• If injectors are clogged, consider using a fuel injector cleaner or replacing the injectors.

5. Check for Vacuum Leaks

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

6. Perform Compression Test

• Remove the spark plugs and insert the compression gauge into each cylinder.
• Crank the engine and record the compression readings for each cylinder. Compare to specifications in the service manual.
• Repair any identified mechanical issues, such as a blown head gasket or worn piston rings.