2001 GMC Jimmy secondary air injection pump

Secondary air injection pump theres a tube(fat, black an rubber) that comes out on the passenger side is disconnected an we cant figure out where it goes. We have had so many people look an can't figure out where it goes.
when the problem happened we was driven down the street an it started losing pressure you could tell it was a hoes the truck still ran an just started to not go any faster then 30 then 20 an now it wont go over 5mph thanks so much