I've noticed a pretty loud hissing noise coming from my throttle/intake manifold/power valve area, although I haven't noticed any vacuum hoses that were obviously disconnected. My question is, can vacuum leaks kill low-end torque? I haven't been too impressed with my Max's low-end torque ever since I bought it last June... last night I checked out my VIAS to see if that L-shaped rod moved at 5000 RPM, and it did, so I assume the Power Valve is operating properly and it has enough vacuum.

Also curious- when I got the car, the little hose above the VIAS control solenoid was disconnected.
although upon closer look at the VIAS diagram vias-diagram.gif
it would appear that hose was the fresh-air vent to close the power valve when it disengages at <5200 RPM, thus disconnecting that hose shouldn't change the operation of the VIAS (only improve it, if that hose is kinked, although that means the Power Valve will ingest dirt/dust/junk from the outside, which could clog/seize the valve later on).
I know that TSB was out regarding low-RPM power loss and how a hose could become kinked, resulting in the Power Valve being open all the time... I'll have to trace that hose all the way and see if that's the case. That same hose connects to a plastic vacuum junction which also connects to the hose to the right of the VIAS solenoid. (the Swirl Control solenoid I believe)

So for the 2nd tangent of this post, has anyone investigated the Swirl control system on 5th gen VQ30DE's? Are there any noticeable differences between a disconnected swirl control solenoid and one that works? What vacuum valve does it use to actuate the swirl valves inside the intake runners? (there's a whole page on AlldataDIY on it, and at the end they show the Power Valve, mentioning that it's part of the VIAS system, which I assume implies that it's separate from the Swirl Control system.)

 

Nevermind, after further research I see the Swirl Control valve is for California models only (of which mine is not)

I'm racking up a few things to tell the dealer when I make a visit (brake rotors, vacuum hissing/leak, jerking in 1st and sometimes 2nd gear that is hard to control...)