Peugeot Boxer high fuel consumption hissing sound

Hey! I had something similar with my Boxer! Same symptoms: check engine light, guzzling fuel, and that hissing. Check your vacuum hoses for splits, especially the one connecting the air filter box to the throttle body. Also, check the air filter itself.

Thanks! Was the hissing constant, or only under acceleration? Did your check engine light come on immediately, or after a while?

The hissing was louder under acceleration. The check engine light took a little while, maybe a day or two of driving with the hissing. Honestly, get it checked at a workshop if you aren't 100% sure. The hose issue can cause other problems if ignored.

It was the intake hose! Replaced it at the workshop for 100€. Fuel consumption is back to normal, the hissing is gone, and the check engine light is off. Thanks for pointing me in the right direction!