my BMW 3 Series E90/E91 (2005-2012) is using too much fuel, what could be the cause?

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to ensure safety during repairs.
• Ensure the engine is cool before starting work.

2. Inspect and Clean MAF Sensor

• Remove the MAF sensor from the intake duct.
• Use MAF sensor cleaner to spray the sensing element carefully.
• Allow it to dry completely before reinstalling.
• Reinstall the sensor and ensure it is securely connected.

3. Replace Air Filter

• Locate the air filter housing and open it.
• Remove the old air filter and inspect the housing for debris.
• Install a new air filter, ensuring it fits snugly.
• Close the air filter housing securely.

4. Replace Spark Plugs

• Remove the ignition coil covers to access the spark plugs.
• Disconnect the ignition coils and pull them out.
• Use a spark plug socket to remove the old spark plugs.
• Install new spark plugs with the correct gap specification (check manufacturer’s specifications).
• Reinstall the ignition coils and covers.

5. Repair or Replace Fuel System Components

• Inspect fuel lines for any visible leaks and replace any damaged sections.
• If the fuel pressure regulator is faulty, remove and replace it according to manufacturer specifications.
• Test or replace any malfunctioning fuel injectors.