Vacuum line question

Help! I have a 1995 Mitsubishi Eclipse 2L Turbo, I replaced the engine with a long block and in the process of conecting all lines I have one line coming off the vacuum canister, that I’m not sure where it connects. One line goes to the air breather and I can’t find out where the other line connects. The engine will run but it will not idle and the canister is drawing air. The diagram located under the hood does not show the canister and the line connections.

My $20 says it connects to the throttle body.

It could be a vacuum supply line for the heater system. Is there a loose hose going into the firewall?

1995 is a fair bit ago, but if it is a vehicle built for US sale, I think there should be a vaccum hose diagram pasted to the engine side of the hood – at least for those parts of the system that affect emissions. However, those diagrams don’t always match the actual layout in the car. I discovered that after I had removed all the vacuum lines in order to replace a blown head gasket in an ancient Mazda GLC. (Didn’t match the shop manual either. My best guess is that the vehicle was assembled when they were phasing in a substantial change in emissions controls.)