There are about 20 vacuum lines. Do you mean a main intake manifold line?
AUTOZONE.COM
I own a 97 pickup with a ka24e and the vacuum diagram is right on the hood. But a local Nissan dealership should be able to print a copy of one from their service manual for you.
vacuum leak
buy a haynes book
get a webber carb idid it runs so good
haynes repair book at auto parts store or get a Nissan truck service manual,check eBay .the dealer wants 75.00.
That info is on pages 18 and 19 of the EF(Engine fuel) & EC(Emission control)section of the 1987 Nissan Truck/Pathfinder service manual.
The vacuum line diagram on a 1985 Chevy Pickup can be found in the service manual. It details not only the location of each line, but its function as well.
Johnsautoparts.com
It depends on what engine. The hemi, does not.
You can find a one line vacuum diagram for 1997 Nissan 1.6 liter engine in the owner's manual. You can also find it at various auto stores.
That year model did not have a modulator valve on the transmission.