1. Check the Spark Plugs

• Remove and inspect the spark plugs for signs of wear or damage.
• If the plugs are dirty, corroded, or fouled, replace them with new ones that are compatible with the 2020 Ford Mustang Mach 1.

2. Inspect the Air Filter

• A clogged air filter can restrict airflow, leading to rough idling.
• Check the air filter for dirt and debris and replace it if necessary.

3. Examine the Fuel System

• Use a fuel system cleaner to remove deposits from the fuel injectors and ensure proper fuel flow.
• Check the fuel pressure to ensure it's within the manufacturer's specifications.

4. Look for Vacuum Leaks

• Inspect vacuum hoses for cracks, breaks, or loose connections.
• Use a vacuum gauge or a smoke machine to detect any leaks in the system.

5. Clean the Throttle Body

• Remove the throttle body and clean it using a throttle body cleaner.
• Ensure the throttle plate moves freely and is not obstructed by carbon deposits.

6. Scan for Error Codes

• Use an OBD-II scanner to check for any stored error codes that could indicate the cause of the rough idling.
• Address any identified issues based on the error codes.

7. Check the Mass Airflow Sensor (MAF)

• Remove the MAF sensor and inspect it for dirt or damage.
• Clean the sensor with a MAF cleaner if necessary or replace it if defective.

8. Review the Idle Air Control Valve (IAC)

• If the Mustang still idles roughly, inspect the IAC valve.
• Clean or replace the IAC valve to ensure it is functioning properly.

9. Examine the Engine Mounts

• Worn or damaged engine mounts can cause vibrations and rough idling.
• Inspect the mounts and replace them if they are compromised.

10. Consider Professional Help

• If you have tried the above steps and the issue persists, consult a professional mechanic for a thorough diagnosis.
• A qualified technician can perform advanced troubleshooting to identify and resolve the underlying problem.