i have a 96 gsr OK, so im using a GSR intake manifold with an obd1 LS throttle body. i've checked the idle air control swapped it with a working one. still the same problem. i checked the FITV took it out, cleaned it. but, unsure how much to screw it in or screw it out to adjust it. right now it's screwed in all the way. the idle pulses from 1500 - 3000 once the car warms up it stays at a steady 2000 rpm then starts to pulse. any ideas?

 

typically that is the IACV...hmm...

Did you check all your vacuum lines to make sure you don't have a leak somewhere?

Is the car showing a check engine light at all?