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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety while working on electrical components.

2. Replace Spark Plugs

• Tools Required: Socket set, torque wrench, spark plug gap tool.
• Remove the engine cover (if applicable) by unscrewing any bolts or clips.
• Use a socket wrench to remove the old spark plugs.
• Check the gap on new spark plugs using a spark plug gap tool; adjust to manufacturer specifications.
• Install new spark plugs by hand, then torque them to the specified value (typically around 15 lb-ft for most Ford applications).
• Reattach the engine cover.

3. Inspect and Replace Ignition Coils

• Tools Required: Socket set, torque wrench.
• Disconnect the electrical connector from each ignition coil.
• Remove the bolts securing the ignition coils and lift them straight up to avoid damaging the plugs.
• Install new ignition coils and torque the bolts to the specified value (usually around 10-15 lb-ft).
• Reconnect the electrical connectors securely.

4. Clean or Replace Fuel Injectors

• Tools Required: Fuel injector cleaning kit or replacement injectors.
• If cleaning, follow the cleaning kit instructions to flush the fuel injectors.
• If replacing, disconnect the fuel lines and electrical connectors from the injectors.
• Remove the old injectors and install new ones, ensuring proper seating and sealing.
• Reconnect all lines and connectors.

5. Check Fuel Pressure

• Tools Required: Fuel pressure gauge.
• Locate the fuel rail test port and attach the fuel pressure gauge.
• Turn the ignition to the "ON" position without starting the engine, and check the pressure reading.
• If pressure is outside of manufacturer specifications, inspect the fuel pump and filter for issues.