my Skoda Octavia NFL (2020-Present) has a rough idle when cold, what should I check?

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative terminal of the battery.
• Allow the engine to cool down completely before starting work.

2. Inspect and Clean the Idle Air Control Valve (IAC)

• Remove the IAC valve from the intake manifold.
• Use a throttle body cleaner to clean the valve and ensure no carbon buildup is present.
• Reinstall the IAC valve and ensure it is securely fastened.

3. Replace Spark Plugs (if necessary)

• Remove the spark plug wires or coils as per your vehicle's specifications.
• Using a spark plug socket, carefully remove the old spark plugs.
• Inspect the old plugs for signs of wear or fouling.
• Install new spark plugs, ensuring they are gapped correctly (refer to the vehicle's specifications).
• Reattach the spark plug wires or coils.

4. Check and Replace the Engine Coolant Temperature Sensor (if faulty)

• Locate the coolant temperature sensor on the engine.
• Disconnect the electrical connector from the sensor.
• Remove the sensor using the appropriate socket.
• Install a new coolant temperature sensor and reconnect the electrical connector.

5. Final Checks

• Reconnect the negative battery terminal.
• Start the engine and allow it to reach operating temperature, monitoring for any rough idle or stalling.