Hi, I recently purchased this blazer & have been tracking down isc hoses that are disconnected. I have a large hose that i can not find the other side for... One side hooks into some big thing on the front of the frame(parallel to the bumper) & has 3 hoses exiting it... one goes to some electrical box right above it, one goes to a weird flat circular thing, which then runs u[p & splits off to other hoses that link up[ in the back of the engine... the one that is disconected is a large... id say 1".... that pops up on the passenger side near radiator & has been cut off..... the device i am talking about is large, has two sections, like a cylindar shape & has a large hardened rubber plunger on the outter facing the bumper.... I have nop clue what im looking for and cant seem to find the vacuum hose routing chart ANYWHERE... one reason, to identify what it hooks i8nto and two, to find out where it goes.... it def looks important & is the probable cause for the extremely rough idle! Thank you!

 

What you are describing has nothing to do with the vacuum system on the truck. It sounds like you are describing the AIR (air injection reaction) system which is an emissions device. It consists of an air pump that is located under the radiator towards the passenger side. The intake for the AIR pump is the hose that runs up the passenger side of the fan shroud and by your description, it is exactly as it should be, slant cut after a right angle in the hose. The outlet from the pump will run to a 'T', then off to each side of the engine where there will be a check valve, then hardline back to the exhaust manifold.

 

I recently purchase a 2001 ZR2 and one hose coming off air pump under radiator sits over the fan shroud and is left open just hanging down the other side. Is this supposed to be left open ?
Thanks,