Hissing sound near EGR

[Silver 99 Camaro]

I had my hood open recently and I can hear a loud hissing when the car idles. I listened carefully and it sounds like it's coming from the EGR area. I could feel no visible leaks, or see any, but the noise is in that area. Any ideas what it could be or what else can make that noise? My only thoughts are EGR valve, intake manifold leak, or a vaccum line. The car is running fine with no other symptoms.

[MattM450]

is it an annoying hissing that seems to be coming from the back of the car? i can hear this from the inside when i drive and my egr valve needs to be replaced but i dont know if thats whats causing the noise

[Silver 99 Camaro]

I can't hear it inside, only when I open the hood. It's from the front of the engine where the EGR is. I don't have any SES codes so it's probably nothing major.