I did all the upper end gaskets on my car yesterday, and on reassembly I found a vacuum that seems to go nowhere. It connects to the underside of the air plenum (86 5.0 MPI engine) on the front vacuum port. The line goes forward on the right (passenger) side of the engine and dips down along the front somewhere under the AC compressor. It runs over towards the fender and was just laying in the battery tray. I did not disconnect this line that I'm aware of, but it is possible that I knocked it loose by accident. Any thoughts on where this thing belongs? I didn't see anything that looks like it has a hose missing, but I may have missed it. The line looks to be 1/4 or 5/16 ID, smaller than the PCV line, but larger than the hard plastic lines.

Found it. There is some sort of canister mounted under the battery tray, and the vac line runs around the battery. I guess it got knocked off at some point by the battery sliding around. I guess this is a message to find a battery hold-down device. Yay for people neglecting to re-install those when changing the battery (no, i didn't do it).

sweet!