Whenever I give the car gas it has a humming/hissing noise coming from the passenger side of the car. I know I don't have an exhaust leak and I checked for vacuum leaks and did not find one. The car idles very high on cold start around 1500 rpm it will drop back down once I start driving but while I am driving it feels like I have a big lose of power. What else should I check for? It sounds like an vacuum leak but I cannot locate it