A quiz: Can you identify this leftover part?

[Esilvester]

Rebuilt the engine after head change and I have a mystery object left over. I have removed all the A/C so I am hoping its part of that...

http://www.flickr.com/photos/edsilvester/6235242062/

[TonyN]

It's an important bit, the short end goes into the lower middle of the intake manifold, the filter goes in the clip above that bit and the long end goes to the boost pressure sensor on the air filter box.

[Esilvester]

Cheers tony. That explains why it's left over... I've not put the air air intake back yet. Great, makes sense. I can relax.