What is this box called and what does it do? 2000 Toyota Tacoma PreRunner SR5 3.4L (5VZ-FE)
I am trying to identify this box attached to the air cleaner hose (just before the throttle body). It's a plastic box with a hose coming out of it that goes to some metal piping. More hosing on the other end of the piping goes to the fuel pressure regulator as a "vacuum sensing line" according to a manual I found. There are no wires or other electronics in it as far as I can tell. It's simply a plastic box. What exactly is this thing called and what does it do?
The larger problem I am trying to solve is diagnosing a P0172 code and I believe I should feel some vacuum from the line coming from this box but I feel none. Is this normal? Is it possible for something in this box to get clogged? I am still very much learning how engines work so that may be a completely wrong assumption. Can anyone help me out please?
