..7747 TBI IAC won't settle down to target RPM

I tried posting this about a week ago but it seems to have disappeared. I have a custom TBI system with a remote IAC feeding the manifold through a rubber hose. Once it goes closed loop the IAC will not settle down to target RPM and runs an average of 200 RPM too fast. Base idle is set and there are no vacuum leaks because, due to the setup, I can pinch the IAC hose and the idle drops about 200 below target idle RPM. The IAC (new) is wired/working correctly because on cold start the fast idle matches the data steam IAC counts and eventually drops but not enough. When grounding the OBD plug (key on engine off) the IAC bottoms out and shuts completely (visually confirmed). Using $42. Any ideas would be appreciated. System runs spectacular except for this.