Ok so I've swapped out 3 diff IACV's and still am having the same problem. When I start the car up (cold start) it idle's high, as it should when cold but it doesn't drop gradually as it warms up, even when fully warmed up still no drop in idle. Once I turn it off then back on it idles perfectly 750 +/-50.

The other strange problem is when pressing the clutch the rpm's take a second or two to respond, like poor de-throttle response if that makes any sense, and then it wont drop below 1200-ish until I come completely to a stop, not when under 15mph and not 5mph, until I come to a COMPLETE stop only then it drops back to the normal 750 +/-50.

I timed it with a timing light at full op. temp. and serv. connector jumped as well. The motor has a blox intake manifold and 65mm tb. I haven't found nor heard any vaccum leaks and I put a rubber nipple over the small fitting on the manifold next to the brake booster fitting.

 

have you adjusted your TPS?
Have you tried the carb cleaner trick around suspected air leak areas like the manifold gasket to the head? Spraying carb cleaner will find a suspected air leak and your idle will change.
Idle air screw on the throttle body?
bad PCV valve?
try putting your finger over the IACV passage while it is running if the car stalls your vacuum is fine if it continues to run you have an air leak somewhere because you plugged the bypass its getting air somewhere else.

 

Well I plugged the hole in the throttle body and the car stalls out immidiately. Not sure what it could be.

 

Check the MAP sensor voltage at idle when the car is at normal operating temp. How long has this problem been happening?

 

try taking off the fast idle valve off. it has 3 10mm bolts then take the cap off the back of the valve should be 2 8mm bolts. once you have that apart try turning the plastic thing that is inside until it is tight. this may solve your idle problem

 

click on the link its another post from Honda-tech this is the ultimate thread for cold idle issues (FIT valve) it shows every detail of cleaning and assembly

https://honda-tech.com/forums/acura-integra-6/%2A%2A%2A-how-%2A%2A%2A-clean-your-fitv-aka-fast-idle-thermo-valve-1564019/