sr20 bouncy idle after 4k rev

[supreme_1]

so i am completely stumped as to what may be wrong

when i start the vehicle (s13 redtop sr20det) it starts up fine and idles at 800 or so. once i rev it up in neutral to right around 4k it will rev up fine, then drop down as normal. But, when the rpm drops it goes to around 500 rpm, then starts jumping from 400-900 rpm without ever settling at a happy medium from here forward.

i checked for vaccume leaks, cleaned my maf (sohc maf), and cleaned and swapped the iacv.

yet with me doing all these things the rpm still bounces.

can anyone lead me in the right direction?

[Couped_up'd]

Low on coolent?

[supreme_1]

nope not at all

[supreme_1]

ok so i narrowed it down to the maf.

i have no idea how its doing this but apparently my car runs the same with my maf hooked up and disconnected. the thing that gets me is that it idles steady at 900 or so until i rev it up, once i rev it, the idle will bounce from 1200 to 500 until i shut the engine off and restart it.

i was under the impression that when i had a bad maf or when its disconnected the engine wouldnt be able to go over 3k? mines apparently can go well past that. any thoughts? its an sr maf.

are there any related sensors that can be causing masking its self behind my maf symptoms?

[JDMRIDDAZ]

Uh the voltage to the iacv circuit...
Check for codes
if you dont get a maf code why would u buy a new maf
unpluggin it and it not changing is weird very
but check for codes and then chec voltage to the iacv..its blk/yellow located at the f9-f10 connect near battery tray area...

[supreme_1]

so i figured out the problem, the ecu that was supposedly good, was faulty. used my buddys ecu to try and sort things out bc my engine diagnostic knob kept spinning to no end.

swapped, ran, cherry. thx