Honda Legend Hissing and Fuel Consumption

Hissing and increased fuel consumption, eh? Sounds familiar! I had similar symptoms in my old Volvo V70. The check engine light was driving me crazy. Have you checked your intake hose for any cracks or loose connections? That was the culprit in my case, letting unmetered air in after the air filter and messing with the fuel economy.

Interesting. You mention the intake hose in your Volvo. Was the hissing sound constant, or did it only occur under certain conditions, like when the turbocharger was engaged?

Good question! The hissing in my Volvo was definitely more noticeable when accelerating, especially when the turbo kicked in. The increased airflow through the leak made it louder. If you suspect a leak, carefully inspect the hose between the air filter, MAF sensor (if you have one), and the throttle body. Honestly, with those symptoms, I'd recommend visiting a trusted workshop and getting the intake system pressure tested. It could save you a lot of time and guesswork.

Thanks for the advice. I took it to the workshop, and you were right. It was a leaking intake hose. Repair cost 100€. Fuel economy is back to normal now.