I have a vacuum hose hanging down in the front of my engine compartment. I cannot find where it goes. It comes from underneath and is long enough to reach the top of the engine. Does anyone know where it might go. The car seems to run ok.

A little more information might help. What year and engine do you have? We'll assume its a Jeep Grand Cherokee unless you tell us different. Need to be a bit more specific than a hose that comes from underneath. Underneath the hood or the engine itself? Describe what/where the connected end of the hose is attatched to. Do you notice your engine running differently? When the engine is running is the hose sucking air at the free end? Does RPM change if you plug it? Be a little more descriptive and someone may be able to offer some assistance. Good Luck.

the hose you are reffering to is the breather hose for the front differential.

It's placement is depended upon the engine you have, on the 5.2L engine the hose should clip on the side of the air box (there are 3 clips on the side of the air box). I have heard on the 4.0L engine the breather line is placed somewhere around the master cylinder.

I have this same problem. I have the hose connected on the front diff side but where is the other side go??? Where is this air box?
1997 Grand Charokee

the AIR BOX is in the engine compartment. It houses the air filter, on the side you will see some small clips the hose clips to these it goes up around and faces down. I have a K&N FIPK II System so I don't have these clips, So I tucked my breather hose between the power steering hose and the power steering reservoir.