how to fix rough idle on my Volkswagen Golf Eighth Generation (2020-present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plugs

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the engine cover if needed.
• Use the spark plug socket to remove the spark plugs.
• Inspect the spark plugs for wear; replace with OEM parts if necessary, ensuring to gap them correctly.
• Torque the new spark plugs to manufacturer specifications (typically around 22 lb-ft).

3. Clean Throttle Body

• Tools Required: Throttle body cleaner, soft cloth, screwdriver.
• Remove the intake duct leading to the throttle body.
• Spray throttle body cleaner onto a soft cloth and gently wipe the throttle body interior to remove carbon deposits.
• Ensure the throttle plate is free to move and reassemble the intake duct.

4. Test and Replace the Idle Air Control Valve (if applicable)

• Tools Required: Socket set.
• Locate the IAC valve, typically mounted on or near the throttle body.
• Disconnect the electrical connector and remove the mounting bolts.
• Inspect for carbon buildup; clean or replace the valve as necessary.
• Reinstall and connect the electrical connector.

5. Inspect Fuel System

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