While driving and idling at a stop (sometimes after I kill the motor too) I hear a hissing/burbling sound coming from the passenger footwell area (up high in the footwell). My first thought was heater core or some such but the heater nor a/c is on.
Sound is independent of idle speed.

Upon inspection under the hood I noticed a small tube sticking out of the firewall, about 1.5-2" long, [in this same area opposite the passenger footwell] that drips water while this is happening. Water is clear. There is no attachment to the little hose nor the appearance of something having been attached. I dont know if this is an overflow that is normal or if something is missing.

In this pic, if you look at the large hose that has yellow writing on it, then look upward from there, near the center of the image, is the little hose in question.



Any ideas what is causing this and if/what I should be doing about it?

Any help is greatly appreciated.
Pablo-