sampey43

Hello guys ive got a problem here and i need some help!!!!!!!!!! I purchased a 2007 shelby gt500 yeaterday and theres a hissing noise coming from underneath the car whenever i put the car in gear and let off the clutch. If the clutch is all the way to the floor or all the way out it doesnt make the noise, just hisses as im letting off the clutch. And it does it in all gears including reverse! Has anybody had this problem or know what could be causing it? The car is stock and has 23,000 miles on it. Hope to here some news, thanks!