how to fix a rough idle on my Volkswagen Golf MK7.5 (2020-Present)

Solution

1. Preparation

• Ensure the vehicle is parked on a level surface with the engine off and cool.
• Disconnect the battery to avoid any electrical issues while working on the vehicle.

2. Replace Spark Plugs

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the ignition coils by unfastening the retaining bolts and disconnecting the wiring harness.
• Use the spark plug socket to remove the old spark plugs.
• Inspect the spark plugs for wear; if they are worn or fouled, replace them with new ones.
• Install new spark plugs, tightening them to the manufacturer's specified torque (usually around 20 Nm).
• Reinstall the ignition coils and reconnect the wiring harness.

3. Clean or Replace Air Filter

• Tools Required: Screwdriver (if necessary for the airbox).
• Open the airbox and remove the air filter.
• Inspect the air filter; if it’s dirty, replace it with a new one.
• If cleaning is an option, use compressed air to blow out debris from the filter.

4. Inspect and Repair Vacuum Leaks

• Tools Required: Smoke machine or carburetor cleaner.
• Visually inspect vacuum hoses for cracks or disconnections.
• If using a smoke machine, introduce smoke into the intake; watch for smoke escaping which indicates a leak.
• Replace any damaged hoses or connections.

5. Test and Adjust Fuel Pressure

• Tools Required: Fuel pressure gauge.
• Locate the fuel rail and connect the fuel pressure gauge.
• Turn the ignition to the "ON" position without starting the engine to check the fuel pressure; it should match the manufacturer’s specifications.
• If pressure is low, check the fuel pump and filter for issues; replace as necessary.