Trying to figure out where this vacuum line goes. 1992 Ranger XLT 3.0 V6 with an auto.

 

Hard to tell from the photo, but it probably goes to your fuel dampener on the fuel rail.

If not there, then you dash controls _ assuming that your dash controls are not working.

 

Dash controls are working. I’ll check the fuel dampener tomorrow and check back. If not, I’ll snap a better photo.

What would you expect to notice if it should be connected to the fuel dampener but isn’t?

 

Nothing, it's a safety feature if the diaphragm ruptures _ if it does, then the fuel is directed into the manifold rather then being sprayed all over the engine bay.

With it disconnected of course, you have a vacuum leak.

It's the only line in that area that runs by the oil filler cap that's near the dampener.
There are not that many vacuum lines on the 3 litres.

Do you have air conditioning ?

 

I think this is it.

1992 FORD RANGER 3.0L V6 Fuel Injection Pressure Regulator | RockAuto

 

Found another loose end that connected to the air box, and they fit nicely together. I'm guessing that's it, although I couldn't tell you the purpose of the line and nothing is different performance wise.

 

Part of the PCV system?

 

Not the PCV (positive crankcase ventilation) system.
There are no small vacuum lines involved in that system.
Two PCV vents in the system, one on each valve cover.
One "ports" directly into where the oil filler cap is.
The other has a PCV valve off the other valve cover and that connects directly into the upper intake manifold.

Maybe you mean the EGR (exhaust gas recirculation) ?
That system does use small vacuum lines, as you may know, but the OP's line is on the opposite side of the engine from where the EGR hardware is.
Plus there would be a CEL if it was disconnected like that _ it would also "ping"

 

I'm not familiar with the older engine bay, so just threw that one out there.