That was the first mod I ever did on a mustang 5.0. You would be hard pressed to find one that is still stock. If the ranger is the same basically it's to reduces intake noise or "woooshing". I thought it sounded better gutted it and it was worth a small bit of power. I didn't care about FE at the time so i have no idea how it affected it. Lol later I used the scoop I pulled out to make a ram air mounted under the facia with a length of dryer hose. I could feel a significant difference at highway speeds with that set up. Of course it also vacuumed up the occasional cigarette butt or piece of paper
.-cheers GW