my Ford Mustang S550 (2015-2023) has a check engine light and a rough idle, what's causing it?

Solution

1. Preparation

• Gather tools: OBD-II scanner, socket set, fuel pressure gauge, multimeter, vacuum gauge.
• Disconnect the battery to ensure safety while working on electrical components.

2. Address Fault Codes

• Connect the OBD-II scanner and retrieve the trouble codes.
• Research the codes to determine the components affected (e.g., P0300 for misfires).
• Clear the codes and perform necessary repairs based on the identified issues.

3. Inspect and Replace Spark Plugs

• Remove the engine cover if necessary.
• Using a socket set, carefully remove each spark plug.
• Inspect for wear and deposits; replace with OEM spark plugs if necessary.
• Reinstall spark plugs and torque to manufacturer specifications (typically 12-15 lb-ft).

4. Check and Replace Ignition Coils

• If misfire codes are present, check ignition coils.
• Disconnect electrical connectors and remove the coils using a socket.
• Inspect for cracks or damage; replace faulty coils with OEM parts.
• Reinstall and reconnect the coils.

5. Clean or Replace Throttle Body

• Disconnect the throttle body electrical connector and intake hose.
• Remove the throttle body using the socket set.
• Clean with throttle body cleaner and a soft cloth; if damaged, replace with an OEM throttle body.
• Reinstall the throttle body and reconnect hoses and connectors.

6. Test and Replace Fuel Pump (if necessary)

• Connect a fuel pressure gauge to the fuel rail.
• Turn the ignition to the "ON" position without starting the engine and check pressure.
• If pressure is below specifications, consider replacing the fuel pump.