My Dinan cold air intake makes a whistle noise for a sec when I rev the engine. I have been told it is just the massive amount of air being sucked in, but it is kind of annoying when you are moving slow and the car whistles every time you hit the gas pedal to move (say around the corner of the drivin or you pull up to the valet). Any suggestions? Also, when do I have to maintanence it? Thanks.