Hey, I just tore in to the top of my engine to replace the lower intake manifold gasket, because I think I have an air leak somewhere under the UIM. By the way, I don't know what automotive god I pissed off, but holy crap what a mess of hoses and wiring under the UIM. It's insane.

Anyway, as I pulled everything loose, I realized that there is a vacuum hose missing off the top of the solenoid on the far right (rear ) of the solenoid rack. The FSM states that it is the pressure regulator solenoid. I checked the vacuum hose diagram, and it looks like the hose runs from the bottom of the ACV to the top of the solenoid.

What does this solenoid do, and what would be the symptoms of the hose being gone? Other than a air/vacuum leak, I would imagine.
Thanks.

 

this solenoid controls the fuel pressure for hot start. Fix it or bypass it but it is important that it is working, if boost doesn't make it to the fuel pressure regulator, you will lack some fuel, running lean and blowing your engine.