i own a 96 12 valve. i noticed underneath the truck there appears to be what looks like a water hose that sits next to the oil pan and in front of the torque converter. can someone tell me what it is? there is alittle bit of oil around the bottom of it. i left my truck running in the driveway and i noticed some kind of pressure or air coming out of it. i can't see where its coming from.

 

That would be your engine/crankcase breather tube. typically you will see a small amount of smoke from it while it runs, as well as a little oil residue.