Throttle Body Air Hoses

[RustyDusty]

Yesterday while taking off the throttle body on the 2.9 in my 1987 ford ranger to get at the ECT sensor I realized there's two large hoses attached to the bottom of the throttle body that are in poor shape. One goes to the crankcase cover, the other connects to the intake manifold. Between these two large hoses is a much smaller one that goes to the charcoal canister. I've gone through all the vacuum lines on the engine and replaced them with silicone lines but missed these ones. I'm wondering if anyone can tell me what they are and if they are under vacuum or not. I've been searching for a vacuum leak that might be causing the engine to stall when I first put the truck into drive or reverse after warming it up. It only dies some days when I first start it for the day. After it dies I start it back up I can put it in drive without stalling.

Anyways I'm going to replace these lines as soon as I can but was wondering if anyone knew their function and if they could be a source of a vacuum leak. Thanks

 

[franklin2]

Not sure about the other hoses but know for a fact the hose that goes to the canister is ahead or upstream of the throttle butterfly. Anything upstream from the throttle body will not be vacuum, just airflow from the aircleaner. Any thing after the throttle blade downstream will be vacuum. The large aluminum intake runner assembly will be vacuum, including the lower manifold.