my Volkswagen Golf MK7 (2015-2019) has a rough idle at stoplights, what could be wrong?

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is off for safety.

2. Replace Spark Plugs

• Sub-steps:
  1. Disconnect the negative battery terminal to prevent electrical shorts.
  2. Remove the engine cover if necessary.
  3. Use a spark plug socket to unscrew and remove the old spark plugs.
  4. Inspect and replace with new spark plugs, ensuring the gap is set to manufacturer specifications.
  5. Reinstall the spark plug wires or coils after securing the new plugs.

3. Clean or Replace Throttle Body

• Sub-steps:
  1. Disconnect the negative battery terminal again.
  2. Remove the air intake duct to access the throttle body.
  3. Use throttle body cleaner and a soft cloth to clean the inside of the throttle body.
  4. If heavily carbonized, consider replacing the throttle body.
  5. Reconnect all hoses and ducts securely.

4. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses for cracks or disconnections.
  2. Use a smoke machine or carb cleaner to identify leaks.
  3. Replace any damaged hoses with OEM parts as needed.

5. Fuel System Inspection

• Sub-steps:
  1. Use a fuel pressure gauge to check the fuel pump pressure against specifications.
  2. If low, consider replacing the fuel filter and/or the fuel pump.
  3. Inspect fuel injectors for clogs and clean or replace if necessary.