I've been chasing a bad boost leak that was faint in sound and seemed to be coming out around in the area of the throttle body. I replaced the TB gasket, TB seals, and hose clamp, but it persisted. I JUST discovered a hanging vacuum line behind the intake, that apparently went to some sensor looking thing directly below the TB. It's mounted to the intake manifold, and has something that looks like a hat shaped diaphragm looking thing on it with a nipple for my loose vacuum line.

What is this, and could it be the source of my leak? I can't do a leak test until the weekend.

 

probably. Can you post pics? Is your car idling weird? What does the vecuum read on you boost guage?

 

I can go try and take some photos, tho its a cramped space.

Yes my idle has been rather crummy for a while, I just replaced my plugs and it made things a little better. The idle will vary a hundred RPM's or so, and occasionally act like it wants to stall.

 

EGR valve.

 

This is a crummy photo with the details sketched in. It has two vacuum lines; one goes toward the center line of the car, one is pointed towards the ground. The one pointed to the center was the one that was disconnected.

My luck (or the lack of it) will make this a separate problem; my crummy idle but not the leak.

 

Its the EGR valve.

 

EGR valve brah