happen to me but idled 1.5k clean the iacv and screw it back in, clean the throttle (good deep clean) and check the coolant lines going to the iacv, let it run for a bit to rid the cleaner then turn car off take the ecu fuse and backup fuse out and let idle for 5mins, also cheack the throttle cable before doing this, thats what i did and mine now idles 1200 when cold then drops to 900-1000 when warm, also got spoon fly and very hi flowing exhaust.