why does my Skoda Octavia's engine revs fluctuate while idling?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect Air Intake System

• Remove the air intake duct to access the throttle body.
• Check for any debris or blockages in the air filter and replace if necessary.
• Inspect the throttle body for carbon buildup and clean it using throttle body cleaner.

3. Check Idle Air Control Valve (IAC)

• Locate the IAC valve, usually mounted on the throttle body.
• Disconnect the electrical connector from the IAC valve.
• Remove the IAC valve from the throttle body, checking for carbon buildup; clean or replace if necessary.

4. Test Throttle Position Sensor (TPS)

• Locate the TPS on the throttle body.
• Use a multimeter to check the resistance across the TPS terminals while slowly moving the throttle.
• If readings are inconsistent or out of specifications, replace the TPS.

5. Inspect Vacuum Hoses

• Visually inspect all vacuum hoses connected to the intake manifold.
• Replace any hoses that show signs of wear, cracking, or looseness.

6. Check Fuel System Pressure

• Connect a fuel pressure gauge to the fuel rail.
• Turn the ignition on (engine off) and check the fuel pressure; it should meet manufacturer specifications.
• If pressure is low, check the fuel pump and filter for clogs or failures.