Corsa Air Intake Leak

That sounds very familiar! I had similar symptoms in my Corsa: higher fuel consumption, engine light, and that hissing. Have you checked the air filter and the hoses around the turbocharger, if your model has one? A leaky vacuum hose can cause those problems.

Thanks. Can you tell me where the leak was in your Corsa, and how you found it?

In my case, the leak was in the intake hose, near the air filter housing. It was a small split, hard to see at first. I used a smoke machine at a local garage to find it. I'd suggest a professional inspection, since the vacuum system is complex. It's better to get it checked properly.

I took it to a workshop. The intake hose was leaking, and the replacement cost 100€. The issues are now resolved.