1990 Olds CC E4MC CCC Carb Idle Issues

My '90 Custom Cruiser has a Y code 307 with a Hot Air Choke E4MC CCC Carb and is having Idle Speed issues. The choke/fast idle will kick off when I tap the accelerator after warm up but it will start speeding back up almost immediately until it is back at fast idle. I can feel it idling fast at red lights and it almost feels like a miss while driving. The engine is fully warm and this even occurs when I park after a 20 mile drive to work, kick it down and it goes back up. Sometimes it will idle down on its own as it warms but most times it does what I just described. Are there any CCC Carb experts out there that could give me a few pointers to look for. I'm thinking a vacuum part or leak but I can't seem to find an obvious one.
things that have been replaced: New transmission, new valve cover gaskets, new rad hoses, new coolant, new oil, no service engine lights.

Any help is greatly appreciated. After this weekend I intend to do a line for line vacuum hose verification.

thanks,
Steve

Put a vacuum gauge on the intake port and see what it reads.
Sounds like a vacuum leak, maybe the intake manifold gasket.