Ok so my Prelude's idle will hang around 600rpm after it is warmed up, and it feels really low, sometimes it will bounce back and forth between 6 and 9. also once in a while, when its low and i try to go it will stall. I checked the battery and the alternator, their both up to voltage specs, and i removed my subs a while ago..what else could be causing this?

 

I would go through the idle adjustment procedure:

1. warm up car completely.
2. while engine is running, unplug electrical connector for the IACV
3. set idle to ~700rpm by turning the idle screw on the throttle body
4. turn off engine, plug IACV back in, reset ECU

Could be other things such as old ignition components; is the CEL on?

 

Check out this thread, its great for solving idle issues,
Mgags7 did a great job with this write-up:

https://honda-tech.com/forums/honda-prelude-4/end-all-idle-surge-bounce-etc-problems-thread-1979500/