Quintanillac5

I purchased my 2000 vette about 8 months ago and since then whenever I turn on my car behind the instrument cluster it sounds like air is being sucked in like an intake. Before it would it only last about 5-10 seconds only when the engine was cold. But lately it does almost every time cold or warm. When the engine is cold the noise goes on until the engine warms up. But when the engine is warm it stays on until I start driving and get to about third gear on the first take off. As I shift through the gears the sound lessons but increase again when shifting between gears until I get to third and then it's gone until I turn off the engine and start it again. I don't what this is, if it's bad, or where to even start to determine what's making this noise. Anyone experiencing this or know a fix for it?