why is my BMW 3 Series G20/G21 (2019-2024) hesitating during acceleration

Solution

1. Preparation

• Gather tools: OBD-II scanner, fuel pressure gauge, socket set, torque wrench, and cleaning supplies.
• Disconnect the negative battery terminal to ensure safety during repairs.

2. Address Fault Codes

• If codes are present, note them and clear them from the system using the OBD-II scanner.
• Reconnect the battery and perform a test drive to see if codes reappear.

3. Inspect and Clean the Throttle Body

• Remove the air intake duct connected to the throttle body.
• Use throttle body cleaner and a soft cloth to clean the throttle plate and surrounding areas.
• Reassemble the air intake duct, ensuring all connections are secure.

4. Replace Spark Plugs

• Remove the ignition coil covers (if applicable) using a socket set.
• Disconnect the ignition coils and remove them from the spark plugs.
• Remove the old spark plugs using a spark plug socket.
• Install new spark plugs, ensuring they are gapped correctly as per manufacturer specifications (typically around 0.030-0.032 inches for BMW).
• Reinstall ignition coils and their connectors, then reassemble any covers.

5. Check and Replace Fuel Filter (if necessary)

• Locate the fuel filter (may be integrated into the fuel pump assembly).
• Depressurize the fuel system by removing the fuel pump fuse and starting the engine until it stalls.
• Disconnect fuel lines from the filter using the appropriate tools, taking care to catch any fuel spillage.
• Install the new fuel filter, ensuring all connections are secure and leak-free.

6. Verify Fuel Pressure

• Reconnect the fuel pump fuse and turn the ignition to the "on" position without starting the engine.
• Use the fuel pressure gauge to check pressure; it should match manufacturer specifications (consult repair manual).
• If pressure is low, further investigate fuel pump or delivery issues.