200TQA...indentify plug on intake manifold and no start

[Nicholas Lawrence]

    I just replaced fuel injectors, seals, and when cleaning off intake
manifold found remains of what may have been a rubber plug.  On the manifold
there is a small hole near injector 4 and 5 with a hose attached to the
under side of the manifold.  Can anyone tell me what this is for? Was there
a plug of some kind in it?
    Still trying to figure out this car.  I think the injectors helped cold
start and hot start, but it still will fail to start and the spark is gone,
no code, and sometimes it will start if I turn the distributor, but there is
no pattern. tonight after 10 miles of easy driving began to loose power,
even with boost on guage no acceleration. Stalled twice but restarted.
    Nick