Originally Posted by Joshuaneufeld1
My 2012 focus s I put a k&n filter on and left cover off, but it sound weird like I lost power or sounds like a boxer motor. Is it supost too?
Many others (including myself) have done the same and got similar results in other threads.
I'd put the cover back on if I were you, but as it's your car, do what you please. If you want more intake noise, get an aftermarket unit.