On the actual elbow, not the IAT, but the other air hose broke off on me. I already bought a part and replaced it ( the plastic elbow, which fits into the small hole on the intake elbow ) and was just curious, what does it do?

 

It's for the opti.

 

Thanks man!

 

That tube feeds metered air to the opti. A second line to the opti connects to the intake manifold to suck the air through the opti.