my BMW 5 Series F10/F11 (2010-2017) has a sudden drop in fuel economy, what could be the cause?

Solution

1. Preparation

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

2. Replace Air Filter

• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Unsnap or unbolt the air filter housing.
  3. Remove the old air filter, ensuring no debris falls into the intake.
  4. Install the new air filter, ensuring a tight seal.
  5. Reassemble the air filter housing and engine cover.

3. Inspect and Clean Fuel Injectors

• Tools Required: Fuel injector cleaning kit, socket set
• Sub-steps:
  1. Disconnect the fuel rail from the injectors.
  2. Remove the fuel injectors from the rail.
  3. Clean each injector using the cleaning kit according to the manufacturer's instructions.
  4. Reinstall the cleaned injectors back into the fuel rail and reconnect.

4. Oxygen Sensor Replacement (if faulty)

• Tools Required: O2 sensor socket, torque wrench
• Sub-steps:
  1. Locate the oxygen sensors (usually before and after the catalytic converter).
  2. Disconnect the wiring harness from the faulty sensor.
  3. Use the O2 sensor socket to remove the sensor from the exhaust.
  4. Install the new oxygen sensor and torque it to the specified value (typically 30-40 Nm).
  5. Reconnect the wiring harness.