The one in the front bottom of the intake under the TB opening?

 

That goes to the EGR valve...on the drivers side of the intake.

 

Here is a visual

 

The only one I can think of that you're talkin about is the coolant line that runs through the bottom of the throttle body. The tube coming out of the driver side of the throttle body goes to the passenger side of the radiator right by the radiator cap. The left tube going into the TB should just be like a 3in 90 degree angle tube that connects to the metal tube that runs down the passenger side of the intake manifold. Not exactly sure which pipe you talkin about but those might be it.

 

He's talking about the pipe in this pic ON the intake manifold, directly behind the waterpump thermostat neck and below the throttle body plenum.