So I've been chasing issues with this car since I bought it, one that has been there from the start is that it has an extremely high idle with out the IAC being connected(like 2k plus), the shop that I got the car from said the IAC must be bad, well 3 IAC later the problem still persists. Now the car drives fine, well as fine as I can tell with out the IAC connected. Could all 3 IAC be bad? Or is it a wiring issue? Any ideas where to start are appreciated.

 

The point of an idle air control valve is to allow more air into the manifold to keep the car running/idling properly. If it is unplugged and you have high idle that means:

1) you have the set screws on the throttle body butterfly set improperly (which is allowing too much air to pass through the throttle body.

2) You have a vacuum leak/disconnected hose which is allowing too much air into the manifold.

Note: I don't have the FSM in front of me at the moment. But generally with the IAC unplugged and the car running it should barely run aka stumble and want to stall.

You can also check the TPS sensor
https://www.rx7club.com/3rd-generati...g-more-170731/

Could also check the AWS and thermowax if you have it. Here is a link to the FSM. there is a trouble-shooting section that can help you better.
Mazda RX-7 Reference Materials

 

Well that's the thing, its a high idle when it is plugged in, when I keep it unplugged it seems to drive fine. The car has a Power FC, not sure if that means I don't need to have the IAC plugged in?

 

Either the IAC is bad or the throttle body settings are out of wack. Re-set the throttle body per the factory service manual and start from there. Make sure the TPS is set in spec.

 

I got almost the same issue but what my are doing is when i plug IAC in idle just go crazy it bounce.