What part is this?!?!?

[Wal92tt]

1999 Expedition EB 4x4 5.4
In the picture it's the 90˚ black rubber elbow just below the thin yellowed vacuum line forming a U. Disregard the yellow circle, I used a picture I've found online. But the part in question is to the right of this yellow circle, almost touching the corner of the black triangular bracket.....
This elbow has melted and disintegrated, allowing a vacuum leak. However, I have no idea what it's called or what system it leads to. Therefore, I have no idea what I'm searching for! I've wasted too many hours looking and I need your help!

 

[Mike Covington]

You meaning the vacuum hose that runs to the egr valve, best thing is to take the elbow off and go match it at an auto parts store.

 

[Wal92tt]

The 90˚ hose connects to a T fitting to the left of the yellow vacuum line.

 

[Habbibie]

There is NO yellow vacuum line in the picture! Theres a green U shaped vacuum line, are you talking about the T hose directly under it?

Ps. That picture says it's from a Navigator...

 

[Wal92tt]

Same engine. The part I need is connected on the right end of that t fitting. Yellow/green, you figured it out......