Vacuum Problems

I have a 1996 Ford Ranger XLT 2.3 4cyl and am having vacuum line problems. The truck will turn over and run for a few seconds and then die. I put new injectors in it a few weeks ago, and plugs and wires, and cleaned air filter. Im suspecting that where the main vacuum line coming from the cannister is faulty. I replace everything from the cannister to the throttle body, all new parts. Now where the stem meets the metal hose coming from the cannister, with the short rubber hose on it, does anyone know if the small metal hose insert into the bigger stem on the throttle body, and the short hose just seals and holds the 2 lines together with the little one inserted into the big one on the throttle body, or does it even matter?