Idle problems

[BKs50trimGST]

Ok guys, i've been having this problem since I fixed my 92 GSX and got it running. My idle revs up and down constantly when I start it and all the way until it warms up. The idle gets better when it's warmed up but still does it. I bought a used idle speed controller from twack about 2 weeks ago and I installed it tonight. That seemed to not help it at all, plus now when I shift gears the idle revs up, thus no bov sound. I have an Apexi S-afc that isn't tuned yet, when I bought the car it already had it in it and I haven't messed with it at all. All help with this is much appreciated.
Thanks Brian K.

[xveganxcowboyx]

Check the resistance between terminals on the ISC. 1 to 2, 2 to 3, 4 to 5, 5 to 6 (I think there are six prongs, but either way you get the idea)

123
456

Should read between 25 and 30. If it's far from that it's broken and either needs repairing or replacing.

Also, a boost leak test is always a smart idea.

[GnArKiLl]

check the ecu for leaking caps..

[JET]

Boost leak test and set the idle.