why does my Volkswagen Golf MK7 (2015-2019) have a rough idle when starting cold

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool before beginning work.

2. Clean or Replace the Throttle Body

• Tools Required: Throttle body cleaner, soft cloth, socket set, screwdriver.
• Remove the air intake duct.
• Disconnect the electrical connector and vacuum lines from the throttle body.
• Unbolt the throttle body from the intake manifold.
• Clean the throttle body with throttle body cleaner and a soft cloth.
• Reinstall the throttle body, ensuring proper torque specifications (typically 10-15 Nm).
• Reconnect the vacuum lines and electrical connector.

3. Inspect and Replace Spark Plugs

• Tools Required: Socket set, torque wrench, anti-seize compound.
• Remove the ignition coil cover if applicable.
• Disconnect the ignition coils and remove them from the spark plug wells.
• Use a spark plug socket to remove the spark plugs.
• Inspect the spark plugs for wear or fouling, replacing them with OEM or equivalent plugs if necessary.
• Apply anti-seize compound to the threads of the new spark plugs and torque them to the manufacturer's specifications (usually 20-30 Nm).
• Reinstall the ignition coils and cover.

4. Replace Engine Coolant Temperature Sensor (if faulty)

• Tools Required: Socket set, pliers, coolant.
• Disconnect the battery.
• Locate the engine coolant temperature sensor.
• Remove the electrical connector and unscrew the sensor from the engine.
• Install the new sensor, ensuring a proper seal.
• Reconnect the electrical connector and the battery.
• Refill coolant if necessary and check for leaks.