Rpm hangs around 1500-2000 when driving, 1200 the rest if the time.

[-Levi-]

Hey everyone.
Posting in the 993 section as the engine is a 95 911 engine in a 911 sc. The engine has the VarioRam intake manifold swap and was recently rebuilt to a 3.8 with supporting internal work.

I have been sorting the engine out since the rebuild and there is one issue remaining that I need help with.

Please see video below. When driving normal or aggressive, the car will idle at 1500-2000 when coming down from higher RPMs. If I drive the car long enough it will eventually drop back to 1200 rpm, but it takes time and the issue will repeat. If I floor the car to redline in first and push the clutch in, the car will hover around 2000 RPM for a while before slowly coming down to 1200 rpm, but it takes time. If at any point I restart the car the idle instantly goes to 1200 rpm. If the car is hot or cold idle is always 11-1200 rpm.

A few things to note.
-When I start the car it instantly fires smooth at 11-1200 rpm, this rpm never goes lower, hot or cold, that is the lowest the idle will be.
-I cleaned the ISV and there is no change
-If I unplug the ISV when warm the car idles perfectly at 800 rpm and the car does not exhibit any of the issues in the video, It’s perfect. EXCEPT, the car will not start when cold.

VIDEO
https://youtube.com/shorts/J1rPkZbHSOs?si=TK9GRSFh4jIiQZ1E
VIDEO

Given the high cost of the ISV, I figured I would post this before blindly replacing it. Additionally I have read that there is a micro switch on the throttle body, would this cause this issue? Any thoughts would be very appreciated.