Hondata

looking for some input on my situation. when its warm outside (70*) i start the car and the idle shoots to 2800rpm and then bounces from 1400-2800 until ECT reachs about 140*

now if i start the car when its cold outside (40*) the idle starts at 1500 and then settles to around 1000. it will still surge a little until warm but nothing too dramatic.

s300 is set to target 1000rpm at idle and the iacv duty cycle is between normal and high. car is obd1 with a victor x intake manifold (no fitv). car pulls 22" of vacuum at warm idle

does this sound mechanical (vac leak or iacv) or can i adjust something in the software?

cliffs: extremely high idle in warm weather when ect is below 140*

Sounds like you have a leak of some kind. Check everything that has to do with idle such as the cold (fast) idle valve and TB gasket.

could the leak go away once warm, causing the idle to go back to normal?

possibly