my BMW 3 Series E90/E91 (2005-2012) has low power and won't accelerate, what's wrong?

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool down before starting work.

2. Replace Air Filter

• Sub-steps:
  1. Open the air filter housing by removing the clips or screws.
  2. Remove the old air filter and inspect the housing for debris.
  3. Install the new air filter, ensuring it fits snugly.
• Tools Required: Screwdriver set (if applicable)

3. Clean Throttle Body

• Sub-steps:
  1. Remove the throttle body from the intake manifold by unscrewing the bolts.
  2. Use throttle body cleaner and a soft cloth to clean the throttle plate and bore.
  3. Reinstall the throttle body and reconnect the electrical connector.
• Tools Required: Socket set, throttle body cleaner

4. Check and Repair Vacuum Leaks

• Sub-steps:
  1. Inspect all vacuum hoses connected to the intake manifold for cracks or disconnects.
  2. Replace any damaged hoses with OEM parts.
  3. Recheck all connections to ensure a tight fit.
• Tools Required: Pliers, hose clamps (if needed)

5. Replace Fuel Filter (if necessary)

• Sub-steps:
  1. Locate the fuel filter (usually along the fuel line).
  2. Depressurize the fuel system by removing the fuel pump fuse and starting the engine until it stalls.
  3. Disconnect the fuel lines from the filter and remove the old filter.
  4. Install the new fuel filter, ensuring correct flow direction.
• Tools Required: Wrench set, safety glasses