I did the Poorman's CAI but with no K&N filter or anything over the opening. I put back the fender's cover in the wheel well and everything, but when I turn off my engine, it makes a sound for a second afterwards as though there are not enough inlets for it to suck the air in, I can describe it as a "hiss." Did you not put the fender cover back on, or made more openings in it to allow more cold air in? Thanks