why does my Volkswagen Passat B8 (2015-2022) engine vibrate when idle

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative terminal from the battery to prevent electrical shorts.

2. Inspect and Replace Engine Mounts

• Tools Required: Socket set, torque wrench, pry bar, jack stands
• Locate the engine mounts (typically found at the front and rear of the engine).
• Use a jack to support the engine gently.
• Remove the bolts securing the engine mount to the engine block and to the chassis.
• Carefully lift the engine slightly to remove the old mount.
• Install the new engine mount and torque the bolts to manufacturer specifications (consult repair manual for exact torque values).
• Repeat for all affected mounts.

3. Replace Spark Plugs and Ignition Coils (if necessary)

• Tools Required: Socket set, torque wrench, spark plug socket
• Remove the ignition coil covers if applicable.
• Disconnect the wiring harness from each ignition coil.
• Remove the ignition coils using the socket set.
• Remove old spark plugs using the spark plug socket.
• Install new spark plugs, hand-tighten, then torque to manufacturer specifications.
• Reinstall ignition coils and reconnect wiring harness.

4. Inspect and Repair Vacuum Leaks

• Tools Required: Smoke machine or propane torch (for leak detection), hose clamps
• Visually inspect all vacuum lines for cracks or disconnections.
• Use a smoke machine to detect leaks while the engine is running.
• Repair or replace any damaged vacuum hoses found.

5. Check and Adjust Idle Speed

• Tools Required: Tachometer
• Start the engine and let it idle.
• Measure the RPM with a tachometer.
• If RPM is outside manufacturer specifications, adjust the idle speed via the throttle body or idle air control valve as per service manual instructions.