On an 87 thunderbird with a 5.0 does the emissions canister return line have a type of electrical plug? The other end of this plug attaches up under the intake. I'm thinking thats where this line is supposed to go. Again toward the end not connected to the intake has a sort of selonoid.
I left the line on from the 3.8l v6, and I believe that should be taken off and this line put on.
There should be a vent hose that runs from the fuel tank to the charcoal canister, then an evap hose that run from the canister to the intake manifold. The evap hose has an evap solenoid with an electrical connector. 3.8L and 5.0L use the same solenoid and lines. I re-used mine. You might as well keep it all connected, it keeps the car from smelling like gas fumes under the hood.