first of all, there are 2 obd2's.
obd2a and obd2b
2a ia in tegs up till and including 2000, and civics till 1999.
if you are throwing your CPS, check your distributor. the plugs there are not the same as on the civic and teg, and that leads to problems a lot of times.
as for the iac, get a helms for both your car and your motor. figure out what the wires are, and go from there.
if its a GSR motor, the extra wire might be part of the IAB's. I don't know. I hate obd2 with a passion