Looking to see if anybody has ran into this problem, I replaced my 46mm stock throttle body on my 87 Shelby CSX with a 52mm throttle body and now my car idles around 2500 rpm. My car ran perfect prior to this swap. I thoroughly cleaned the used T.B. I purchased, reused the T.P.S. Sensor and A.I.S. Motor from my oem T.B. Installed a new gasket and now it will not idle down below 2500 rpm even with the idle set screw backed all the way out, I also read NAS sticky on how to reset the A.I.S. Motor and nothing has changed, I rechecked ALL my NEW vacuum lines installed last year and found no problems. Anyone have an idea on what could be causing this?