Identifying this hose on intake manifold

What year truck

And yes #2 appears to be the PCV valve hose. Easy enough to tell, pull the hose and see if the nipple has a nut at the base that would be the PCV valve

In the second diagram the hose you are looking for is 11826+D and the PCV Valve is 11810

The PCV valve can be unscrewed from the manifold and cleaned or replaced (if parts are available).

Last year I replaced the timing belt and decided to replace as many hoses as I could while I was at it. I could not find that hose, either, so I bought a length of hose from the local auto parts and just hooked it up by making a ¾ loop of hose instead of the tight bend. Looking at it with a pragmatic eye, all it needs is to be connected with a hose that can pass crankcase gasses. (Did I just say "pass gas"? )

Recently replaced my positive crankcase valve (pcv) it connected to hose #2.

#1 is a coolant port hose. You can absolutely bypass the coolant passages on the manifold by looping the two hoses on the passenger side rear of the manifold (all others are basically connected to those) but you need to remove the wax pellet off the throttle body cam.

The coolant pipes WILL rust out (mine were probably 2-3 years away from leaking out) and there's no replacements.

#2 is PCV and passes from the passenger side. A molded hose is 100% necessary.