2005 Maxima - What's this hose?
 

Hi all. Our Maxima has started misfiring and shaking today, giving either a solid or a blinking Check Engine light (I'm not sure why it changes) throwing error codes P0305 and (pending) P0300. I'm under the impression that I'm going to need to take a lot of stuff apart just to remove the 05 spark plug and coil, which I'm really not looking forward to. But while I was looking under the hood, I noticed a hose that has an end that's not connected to anything. I'm sure it's nothing to do with the error codes & knocking, but could someone tell me what this is please? The pictures are two different angles showing the same hose, with the second photo looking in from across the battery.
https://cimg7.ibsrv.net/gimg/maxima....07ab02cd92.jpg

I wanna say it is a breather hose. i think for the transmission. I may be wrong about the transmission though.

Ah, that helps. I was thinking something had sheared off without me knowing about it. Thanks for the reply!

Thanks for the confirmation, it's much appreciated :)