You are looking for an ODBII port. It will most likely have about 4 wires, you will need to get a wiring diagram for the donor car/PCM that you are using to see where it needs to be connected. Since the connector is a standard ODBII connector you could get one from almost any car made between 1996 and 2004.
Pretty much any GM 96 and newer will have one so wreckers should be a good source. For earlier ones like GTPs pin 2 is purple which is class II data from the PCM, pins 4 and 5 are black which are grounds, pin 9 is tan which is uart data from the PCM and pin 16 is orange which is constant +12 volts. Pin 14 is dark green but do not need this on a Fiero swap. Dan
