how to fix rough idle on Ford F-150 14th Generation (2021-2024) with P0171 code

Learn how to diagnose and fix P0171 rough idle in Ford F-150 14th Generation (2021-2024). Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

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

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses connected to the intake manifold and throttle body.
  2. Use a smoke machine or carb cleaner to detect vacuum leaks.
  3. Replace any damaged hoses or tighten loose connections.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Locate the MAF sensor, typically situated between the air filter and throttle body.
  2. Disconnect the electrical connector and remove the MAF sensor using a Torx or socket wrench.
  3. If cleaning, spray MAF cleaner onto the sensor element; if damaged, replace with a new sensor.
  4. Reinstall the MAF sensor and reconnect the electrical connector.

4. Throttle Body Cleaning

• Sub-steps:
  1. Remove the air intake duct connected to the throttle body.
  2. Use throttle body cleaner and a clean cloth to remove carbon deposits from the throttle plate and bore.
  3. Reinstall the intake duct securely.

5. Fuel System Inspection

• Sub-steps:
  1. Check the fuel pump operation by listening for the pump sound when turning the ignition to the "ON" position.
  2. Test fuel pressure with a fuel pressure gauge; it should meet specifications (usually around 40-60 psi).
  3. If fuel pressure is low, consider replacing the fuel pump or filter.

6. Oxygen Sensor Check

• Sub-steps:
  1. Inspect the upstream oxygen sensor wiring for damage.
  2. Use a multimeter to test the sensor’s voltage output; replace the sensor if readings are outside specifications.