Peugeot 106 Hissing Noise and Fuel Consumption

Sounds familiar! I had almost the same thing happen with my old Opel Corsa. Exact same symptoms: check engine light, higher fuel consumption, and that hissing sound! It turned out to be a split in the intake hose after the air filter. Maybe check that? If air is getting in after the airflow sensor, the engine management system gets all confused.

Interesting! Where exactly should I be looking for this intake hose? Is it near the throttle body, or closer to the air filter? Also, would a small leak really cause all these problems? I thought it might be something more serious, like the turbocharger or the intake manifold gasket. I don’t have much experience so how worried should I be?

On my Corsa, it was between the air filter box and the throttle body, so trace the air flow. It doesn't have to be massive, even a small split can cause havoc with the air/fuel mixture and trigger the check engine light. It's probably best to get it checked out by a mechanic, they'll have the right tools to properly diagnose it. Hopefully it's just a hose, but it’s hard to be certain.

Thanks for the advice! I took it to a local workshop, and they confirmed it was indeed a split intake hose. Cost me 100€ to get it replaced, but at least it's sorted now. The hissing is gone, the check engine light is off, and the fuel consumption seems back to normal. I really appreciate the help!