how to diagnose rough idle on a Ford F-150 13th Generation (2015-2020)

Solution

1. Preparation

• Tools Required: OBD-II scanner, basic socket set, fuel pressure gauge, vacuum gauge, throttle body cleaner, and a multimeter.
• Ensure the vehicle is parked on a level surface and the engine is off.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Address Engine Codes

• Reconnect the battery and start the engine.
• If any error codes were found in the diagnostic step, address them by repairing or replacing the faulty components as indicated.

3. Clean or Replace Air Filter

• Locate the air filter housing and open it.
• Remove the air filter and inspect for dirt and debris.
• Replace with a new air filter or clean it if reusable, ensuring it fits securely back into the housing.

4. Inspect and Clean Throttle Body

• Remove the air intake duct connected to the throttle body.
• Using throttle body cleaner, spray and wipe clean the throttle plate and inside of the throttle body.
• Ensure the throttle plate moves freely and reconnect the duct.

5. Check and Replace Spark Plugs/Ignition Coils

• Remove the ignition coils using a socket set.
• Inspect the spark plugs for wear; replace if they show signs of fouling or damage.
• Install new spark plugs to the manufacturer’s torque specifications (typically 12-15 lb-ft) and reinstall ignition coils.

6. Test Fuel System

• Connect the fuel pressure gauge to the fuel rail’s service port.
• Start the engine and check the fuel pressure; it should match manufacturer specifications (usually around 40-60 psi).
• If pressure is low, inspect and replace the fuel filter, fuel pump, or injectors as necessary.

7. Vacuum Leak Repair

• Use a vacuum gauge to check for proper vacuum; diagnose any leaks by inspecting hoses and gaskets.
• Replace any faulty vacuum hoses or gaskets to ensure a proper seal.