my BMW 5 Series F10/F11 (2010-2017) has a rough start when cold what could be wrong

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety during repairs.

2. Inspect and Replace Spark Plugs

• Remove the engine cover using a socket set.
• Disconnect ignition coils from each spark plug.
• Remove spark plugs using a spark plug socket.
• Inspect spark plugs for wear; replace if necessary with OEM-spec plugs. Torque to manufacturer specifications (typically around 20 Nm).
• Reattach ignition coils and engine cover.

3. Test and Replace Fuel System Components

• Use a fuel pressure gauge to check fuel pressure at the rail; it should be within specified values (consult the service manual for exact numbers).
• If pressure is low, replace the fuel filter and inspect the fuel pump.
• Check the fuel injectors for proper function; clean or replace if they are clogged.

4. Replace Coolant Temperature Sensor

• Locate the coolant temperature sensor (usually near the thermostat housing).
• Disconnect the electrical connector and remove the sensor using a wrench.
• Install the new sensor and reconnect the electrical connector. Torque to manufacturer's specifications.

5. Inspect and Repair Intake System

• Visually inspect all intake hoses for cracks or leaks.
• Replace any damaged hoses.
• Clean the throttle body using an appropriate cleaner and a soft cloth.