shes studdering!

i just installed my Ebay CAI and i used the Filter that came with the CAI, now every once in awhile when i try to start it studders leading me to think its trying to choke down some air to start it and the new CAI isnt letting it... is this possible? The only thing that went askew during the installation is there is a rubber tube that didnt reach all the way to the base of the CAI so i went a bought a rubber tube from Pep boys with a hose clamp and cut it and clamped it to the CAI and it fit into the engine like a glove.. where exactly does that tube lead to? and how important is it... what does it do?