Skoda Roomster Fuel Consumption and Hissing Sound

That does sound like an intake leak. A hissing sound upon acceleration is a classic symptom! High fuel consumption and the check engine light are also telltale signs. Have you checked your air filter recently? A clogged filter can sometimes exacerbate issues with the turbocharger system. The engine misfire might be related to the lean condition caused by unmetered air entering the intake manifold. You might try a leak detection spray. Be careful!

Thank you for your reply. I am not familiar with a 'leak detection spray'. Could you elaborate on how that is used, and where I would apply it?

Yes, a leak detection spray is used to find vacuum leaks in the intake. However, given the symptoms and your limited experience, it is best to consult a qualified mechanic. It does sound like an intake hose is leaking. This is a common problem. They can diagnose it properly and prevent any damage to the turbocharger. I still believe that going to the workshop would be the best course of action.

I appreciate the assistance. I took it to a mechanic who confirmed a leak in the intake hose. The hose was replaced, and the total cost was 100€. The car is now running smoothly.