The best way I can describe it is like this:
The stray line terminates at the filter housing on the passenger side of the vehicle, it routes through a few hangers on the filter box, toward the air intake pipe. Then it joins another vacuum hose connecting to an upside down "F" shaped plastic junction fitting with three hoses attached to it. One hose is the stray hose, another routes to a plastic box a few inches from the fitting. And they all routthrough a little plastic valve (I think it isa check valve) up toward the firewall, then it attaches to a hard pipe on the firewall from there it goes to a fitting on driver side of the intake manifold. It appears that it goes through the manifold on the driver side and into a hose labeled "24" as it attaches with a bunch of other hoses into a box on the driver side above the wheel well.

 

Your description is difficult to overlay on my 90 Accord vacuum diagram from my Honda Shop Manual. Best I can suggest is perhaps the loose line connects to one of the 4 vaccum supply nipples on the entry end of the throttle body. The plastic box (about 5"x5"x5" but not square) on the firewall should have 5 vacuum lines (3 upper and 2 lower lines). The three upper lines connect to the vacuum supply nipples on the entrance to the throttle body, 2 to the upper row of three nipples, and 1 to the single lower nipple. The 4th nipple attaches to the long vacuum line that hangs beneath the air intake duct and has a check valve in the line.

good luck

 

After reading through my post, I realized that I may have been unclear with which vehicle I am having trouble with. The misplaced vacuum line is on the 1994 Accord EX.
I will take a photo of the engine compartment and try to explain better what I am talking about. I am hoping to find a 94 Accord that I can look at near my house.

 

Yes, that helps a lot.

I believe the stray line is a vacuum supply line to the Intake Air Resonator Control solenoid valve. The location of the solenoid valve is just below the intake air filter box. The other line from the F-tee goes to the intake air resonator vacuum reservoir box. Purpose of intake air resonator is to reduce air inlet noise (that some folks prefer to hear).

There is a shop manual download from http://www.hondahookup.com/manuals/for the 94-97 Accords that will provide additional sketches to help.

good luck

 

Is the resonator valve supposed to be inside the big box that is mounted under the air filter housing (in the fender well) I took it off the other day to try to find a connection and found nothing. Just a half "S" shaped tube going through the box and the filter housing mounts to one side and a weird shaped Half "S" (a little like a plumbers P-trap) mounts to the top in front of the filter housing next to the battery. It has a moveable flap on the top of it.....no idea what that is for.
So am I missing the intake air resonator control solenoid valve?
Is it worth having? or should I just plug it off?

 

I doubt plugging off will cause any problems. I have a 94ex and would have to look under hood to locate. I've never worked on that system at all.

good luck

 

I looked at my 94EX this evening and here's what I found.

The intake air resonator valve is a tall slim round assy w/ an electrical connector, black cap and two vertically stacked vacuum connections on bottom end. Lower connection has vacuum line to the F-tee and upper connection has a short vacuum line that curls upwards and plugs into the top side of the intake air resonator (beside the battery and air filter box). Finally, I saw asingle vacuum line from the F-connector traveling to the intake air resonator vacuum tank, consistent w/ the manual.

Did you download the manual? This will help you identify parts and locate them.

good luck