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.

 

:-l

 

try and find your leak with a good ole can of carb cleaner spray around gaskets while the engine is running, if it stutters and the RPM's drop you found your leak. (if you have one)

what is your setup? motor, ECU , Engine Managment? year? OBD?

 

i had a issue like that befor my tps sensor went, grabed a blox one fixed that issue, also the fast idle thermal valve, or fitv in short can cause those problems search up that issue and see if that sounds right, you can make a block off plate for it as i did, if your motor has one. Also cover all uncaped nipples with vacume covers