Coupla questions about vacuum and a supposed heat shield?

[conley]

Hello. I am a newb here, but have had an 82 C10 in the family for a long time. Fell to my hands eventually, and I have been trying to get it back in running condition. Unfortunately, AZ has rather strict emissions compared to ol NM where the truck was last registered, and it's not passing. I have been trying to identify the problem and was following all the vacuum hoses along according to the emissions label diagram, and I discovered that a few of them don't exactly go where they're supposed to. For example, according to the diagram, the hose from the distributor is supposed to split and go to the efe/manifold TVS and the carb, but it only goes into the carb, just below the filter. Not sure if maybe the diagram isn't exactly correct, or if someone kinda cobbled together their own vacuum system. Aside from this, i'm missing the whole snorkel assembly from the air cleaner to the duct in the grille, including the part that the thermostatic air cleaner part that changes the amount of hot vs cold air that comes back in. So basically it's sucking hot engine air all the time.
Anyways, the truck runs rich, putting out about 2.5x the legal amount of hydrocarbons. The EFE exhaust valve works, the EGR appears to be working (it moves and makes the engine stall when manually pressed). My coolant gauge flings wildly about whenever the truck is warm and driving however, so I was thinking perhaps its the coolant temp switch?

Sorry for the novel. Anybody got any ideas?