Rb20det high idle (2500 rpm) need help asap

[redrocket]

ok, so i have an RB20 swapped s13 and just the other day as i got home i noticed that the idle was way up (2500 rpm). i checked for vac leaks as best as i could, the car still holds boost (10psi) and runs fine while driving but in and out of gear will not want to go below 2500rpm. i tried a new maf, nothing. took apart and cleaned IACV, nothing. cleaned PCV, nothing. now i know im not supposed to do this with no voltmeter but i tried to lower the rpm via the tps by rotating it counter clockwise so i know it is not on proper voltage, the IACV screw is also all the way in btw. the ecu is throwing one code which is code 54 (A/T control unit to ECU) as the chassis was auto prior to swap so thats irrelivant anyway. i feel like ive exhausted my resources and knowledge so any insight to this problem, what it might be, and how to fix it will be greatly appreciated. tomorrow ill be changing the tps and setting it with a voltmeter, as well as changing the o2 just for the hell of it. thanks guys

[Skym]

When IACV is faulty or sticky (due to oil deposits), it can become stuck open thus providing too much air to intake plenum. IACV + AACV give engine a higher idle when cold to combat rich mixture and as IACV closes (ECU makes engine go leaner at same time), the idle rpm drops.

Remove IACV and put IACV on a hot plate and apply voltage via battery to see if it closes. If closes, see how long it takes to close. Sometimes have to replace IACV.

Also if car was auto, you need to adjust the timing on the kick down tables that can cause rpm to flare up and idle high when TPS is on idle contact.

[redrocket]

When IACV is faulty or sticky (due to oil deposits), it can become stuck open thus providing too much air to intake plenum. IACV + AACV give engine a higher idle when cold to combat rich mixture and as IACV closes (ECU makes engine go leaner at same time), the idle rpm drops.

Remove IACV and put IACV on a hot plate and apply voltage via battery to see if it closes. If closes, see how long it takes to close. Sometimes have to replace IACV.

Also if car was auto, you need to adjust the timing on the kick down tables that can cause rpm to flare up and idle high when TPS is on idle contact.

The chassis was auto but I doubt the rb20 was ever auto. I'm not sure

[redrocket]

AAC valve took a ****... easiest test, easiest diagnosis, used pliers to determine that... now i feel stupid that i wasted two days wracking my brain when all i shoulda done was cut flow to the iacv and aacv in the first place.