Skoda Yeti Fuel Economy and Hissing Sound

Regarding your Skoda Yeti's symptoms, it does sound like an air leak. I had a similar issue with my old Vauxhall Astra. Check engine light, poor fuel economy, and a hissing sound were all present. Have you inspected the intake hoses, specifically the ones connecting the air filter to the throttle body and the turbocharger, if your Yeti has one? Also, consider examining the intake manifold gasket for any signs of damage or wear. Is the hissing sound constant or does it only happen under acceleration?

Thanks for the quick response. I've had a quick look at the intake hoses, but couldn't see any obvious cracks. I'm not really sure what I'm looking for though. Where exactly should I be focusing my leak detection efforts? Is there a common spot where these hoses tend to fail? Also, I am not sure if the Yeti has a turbocharger.

Given that you cannot visually identify any cracks, the leak might be small or located on the underside of the hose. Air intake hoses are often made of rubber, which can degrade over time due to heat and exposure to the elements. The most common failure points are where the hose connects to the throttle body or the intake manifold. The hissing sound is a key indicator; it is like when a balloon deflates slowly, that is a telltale sign of a leak somewhere in the intake system. Considering the symptoms and your vehicle's age, I would suggest having a workshop perform a smoke test to pinpoint the exact location of the leak. The cost of repair should be relatively low, assuming it is just a hose replacement.

Skoda Yeti air leak resolved. The workshop confirmed a split in the intake hose. A new hose was fitted, and the check engine light is now off. Fuel economy is back to normal. The total cost was 100€ Thanks for the help.