Taurus Hissing Sound Fuel Consumption Issue

I had something similar happen with my Taurus. It sounds like you might have an air intake leak. The hissing sound when accelerating is a big clue. When was the last time you checked the intake hose between the air filter and the engine? Is it cracked or loose? That can definitely cause those symptoms. Does the engine feel like it's misfiring at all?

Thanks for the tip! I haven't specifically checked the intake hose, I'll take a look. Where exactly is that located? And if it is cracked, is that something I can easily fix myself, or am I better off taking it to a shop? About the engine misfiring, how would I notice it?

The intake hose runs from the air filter box to the intake manifold on top of the engine. Follow the big black hose from the air filter, you can't miss it. A cracked hose will cause unmetered air to enter the engine, leading to higher fuel consumption and the check engine light coming on. If you're not mechanically inclined, I'd suggest taking it to a shop. You could try to replace it yourself, but you'll need some basic tools, and you have to make sure it's properly sealed. Misfiring feels like the engine is stumbling and shaking a bit more than usual.

Thanks a lot for your help! I checked the intake hose and you were right, it had a big crack in it. I took it to a local shop, and they replaced the hose. Cost me about 100€, but the hissing is gone, the check engine light is off, and my fuel consumption seems back to normal. Appreciate the advice!