i was tightening my throttle cable a minute ago and noticed this little rubber fitting. it squeals when my engine is running and almost seems like its not supposed to be rubber. looks like air is being sucked through it and it almost closes up b/c of the pressure of sucking air causing it to squeal. can anyone tell me what part this is so i can replace it? thanks
and its the rubber hose my fingers pointing to. and i can get a more broad view picture of it if you cant really tell what it is. just lemme know

 

Looks like a heater hose?

 

i cant tell from the pic, but it might be a vacuum hose, those are usually reinforced to prevent them from caving in and usually dont make noises, one way to tell is to unhook it and if it kills your engine when running (or makes it run terrible) then its a vac hose, there isnt a reason why a heater hose would make any noise cept maybe slight gurgling but thats not common

 

also, old vac hoses (egr, pcv, and such) will get brittle with age and collapse on themselves, pretty common on most any vehicle, some ppl will swap it out with stock hose, which is a easy temp fix, but it needs to be reinforced to prevent it from collapsing under vacuum

 

that is a vacuume hose that is connected i believe to the EGR system, it goes into the bottom of the throttle body to the right of the picture, and off the top of the picture, it runs behind the block, infront of the firewall, and disappears...

we found that was cracked and caved in on my buddy's sport trac last wednesday, it sets off all kinds of codes too... we took it off, (used slip joint pliers to break the seal on each end, then pulled, it's not glued or clamped) and wrapped it in electrical tape, put it back on, and you can't hear it hissing anymore

it is supposed to be rubber, and it isn't reinforced like it should be, it's quite soft... JY for a new one

 

That hose is for the PCV valve. It has vaccume because it runs off the intake so it will squeal. The part is like $25 at the dealer or you can fix the one you got by finding a hose that will fit on the end of the plastic line and the bottom of the intake manifold