crazy fluctuating idle - apexi pfc djetro, everythings legit

[alesserfate]

heres the deal

after my car warms up the idle starts revving between 500 and 1500 rpm going up and down whenever i come to a stop at a light, its pretty fucking annoying

car: s13 sr20det, apexi metal hg/arpstuds, sard 850s, greddy im, gt30, apexi power fc djetro, has a good tune makes 411whp

sometimes after a little driving it stops doing that, and when it does taht if i blip the throttle as its about to drop and get it dead on, it will stop and idle normally

what i've checked:
-vacum leak tested everything from the intake filter, no leaks
-checked grounds on the IACV, it's fine
-tried changing the idle on the pfc, no effect
-IACV gaskets are fine

also, this exact setup was in my old car before and it was fine, the only things iv'e changed are the engine wiring harness, and i've had it retuned for a little more power

on another note, until the car warms up completely, if i touch the throttle as its doing its crazy fluctuation, on its way 'revving down' down, i can smash the pedal all i want until 100% and there will be no response at all until it goes back into its upwards cycle towards 1500

once i start driving, until its completely warmed up, every time i shift gears (hence letting off the gas when upshifting) the moment i step on the gas again there is 0 response, once again, even if i floor it, for a few seconds, and then all of the sudden it comes alive

I have an AEM wideband, and as its revving down, it leans out all the way, then it riches out, then leans out again

I was thinking it could be my TPS ?

any other tips ?

i can't come up with anything else to check.