how to fix rough idle on my Volkswagen Passat B8 (2015-2022)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to prevent electrical shorts.
• Ensure the engine is cool before beginning work.

2. Addressing Air Intake Issues

• Inspect Air Filter:

  1. Remove the air filter housing cover using a socket set.
  2. Inspect the air filter; replace if dirty or clogged.

• Check for Intake Leaks:

  1. Inspect all hoses and connections in the intake system for signs of wear.
  2. Replace any damaged hoses or use clamps to secure loose connections.

3. Spark Plug and Ignition System Repair

• Replace Spark Plugs:
  1. Remove the ignition coil connectors and unscrew the coils.
  2. Use a spark plug socket to remove old spark plugs.
  3. Install new spark plugs, ensuring they are gapped correctly (consult manufacturer specifications).
  4. Reinstall ignition coils and connectors.

4. Throttle Body Cleaning

• 1. Remove the air intake duct to access the throttle body.
• 1. Use throttle body cleaner to spray inside the throttle body.
• 1. Use a clean cloth to wipe away carbon buildup and debris.
• 1. Reassemble the air intake duct securely.

5. Fuel System Inspection

• Test Fuel Pressure:
  1. Connect a fuel pressure gauge to the fuel rail service port.
  2. Turn the ignition to the "On" position (do not start) to check for proper fuel pressure.
  3. If pressure is low, check the fuel pump and filter for issues.