Well not to sure how to describe this but when I had the hood up on my truck I noticed that when I hit the throttle I could hear air suck into the intake. It sounds as if there might be a hose or tube off around the intake area but not sure because I cant see anything off. It sounds as if the the tube or whatever it is closes itself off after just a second. You cannot hear it with the hood shut nor does it make it run any different. Is this normal on these trucks or do I have a problem somewhere? Any input would be greatly appreciated. Almost forgot to mention that it is an 06 4x2 with 4.0 if that matters. Thanks in advance!