Trying to find leak... Does this look right?
 

While taking a quick look to find a vacuum line not connected, I spot this - does this look correct? If so, does anyone know what it is for? Pressure relief?
http://986forum.com/forums/uploads02/plug1467242393.jpg

No, that is not correct. Trace the line back and see where it goes, but the factory never did that.

Here are some more pics. It's hard for me to see where it goes, but looks like its under the intake above the transmission.

Also, just playing around, when the A/C is on, the MAF readings jump from 2.75 g/s to 4.0 g/s at idle @ 700 rpm.

http://986forum.com/forums/uploads02...1467244863.jpg
http://986forum.com/forums/uploads02...1467244879.jpg

Is the car a Tiptronic?

Yes, it is.

All the pictures I can find show this hose routed across the middle of the Engine, but none of my manuals show what it is, or where is goes. :confused:

Hello Boxy_02,

because i couldn't see anything on your pictures, i adjusted them. Looks like somebody fitted this line with a blind plug.

Is that photo taken from the left side of the car?
http://986forum.com/forums/uploads02...1467287946.jpg

And from where did you take this photo?
http://986forum.com/forums/uploads02...1467287962.jpg

Is it a 2.5 Litre engine with AT?

Regards, Markus

They were both taken from the passenger side, 2002 - 2.7L Auto.
The 2nd photo shows where the hose is going, towards the rear.

I would be willing to bet that someone has disconnected the Tiptronic cooling valve system because it had a problem, and they did not want to pay the $ to fix it correctly. If that hose traces back to the Tip, you need to reconnect it to the cooling system and fix the problem, running without the system connected is going to kill your transmission.