Intake noise, help plz.. Options

[mikecelica]

Its been a while now that my cars had this hissing kinda sound like air escaping from somewhere..i hear it its under the hood (no exhaust problems, checked). i think it might be the intake tube. The tube is conected to the intake manifiold, and a cone filter at the end. on the tube tho thers two holes, one for the air sensor,but whats the other for? it has a little nipple and it came wit a rubber thin hose but im not sure is it suposed to plug into somewhere of the engine/manifold? any helps. thanks

[94TRDcelica]

There are three holes in my induction pipe (HKS) one for the sensor the other two are located further along near where it joins the manifold. One is small 15mm ish 90 degree pipe that connects straight below the intake valve. This creates a heavy vacuum/sucking noise when not connected so check this for splits/connection, the other feeds around towards the actuator, its a small bore vacuum pipe check this too. Other check is the small pipe leading from the rocker to the intake manifold, the oil blow bypass, this is also under heavy vacuum.

Hope that helps