1990 Firebird 3.1 vacumn line question

[lehawk]

I replaced my son's blown 3.1 engine with a used engine which is in and runs fine but I have a vacumn line I can't figure out where it goes. On the rear of the throttle body are two vacumn lines. The larger one goes to the MAP sensor on the passenger firewall and the smaller diameter one goes to a tee. One side of the tee goes to the (I can't think of what it is called to save my soul at the moment) input under the upper plenum. My question is where does the other side of that tee go? I have searched and for the life of me can't find anything unplugged. Any help would be greatly appreciated.

Thanks,

Bob

[2.8RS]

That other line may go to the charcoal canister, its the black cylinder behind the driverside headlight. That would be all that I can think of, I have a 2.8 and there are some differences.