Hi, i have a supercharged civic d16y8, cams, ported head, oversized valves, aem CAI.... etc. So i had change my oem TB for a 70mm skunk2 TB. Now the idle speed is 2500 rpm and over, i had tested the IAC, TPS and all of them are ok, the idle screw it's totally closed, the TPS it's outputting 0.5 V in close position. When i put the oem TB back the problem dissapear.

What do you know about this?

 

Obviously, the engine is sucking more air than it's supposed to, thus the high idle. Any open vacuum lines? Does the throttle plate close enough?

 

you might have a vacumm leak. spray some carb cleaner around the area and see if you see/hear any engine change. if so thats where the leak is