i have done research and alot of trouble shooting for months now and still cannot resolve the issue. when i start my car it idles fine but once it warms up to operating temp the idle surges. also while driving the rpm's like to stick at 3000 and will not go back down unless i rev the car up once or twice or turn it off for 5-10 sec. i swapped and cleaned my IACV with a known working one and the FITV is clean too, i also adjusted the TPS. i dont kno what else to do now. any help would be appreciated.

 

have you checked for any intake leaks? cracked or broken hoses on the intake manifold.

 

my sol is doing the same thing, i could find no intake leaks, altough it is a common problem, my iacv is fairly new...check for your pcv valve on the top of the intake right under the fuel rail, if not that then i was given a tip that it could be a coolant temp sensor (engine revs higher to achieve hotter temps)

 

I jammed my arms behind the intake manifold and one of the lower studs holding it on is missing a nut and the gasket is brittle so im going to replace it and see what happens.

 

The pcv is new. As for the temp sensor I never thought of that. I looked it up and a bad temp sensor it will throw a CEL. I have no CEL thanks though.

 

I had the same problem with a d16z6 i blocked off the fitv with a block off plate and just connected the 2 hoses together and it fixed the problem for me i dont know if your interested in trying that tho