My car has the code for the eld and a horribly unstable idle. Eventually it settles down, but only after every person in the surrounding area thinks I'm trying to rev on them. My car does not have the eld or any provision for it, I have no idea of what it even does or how it works. My swapped in motor is a 95 ls. Is the eld thing be what's causing my idle problems? I already changed the IACV and it still does it. If it is the eld, how do I fool the ecu into thinking it's connected/how do I connect it?
thanks for any help..

 

It detect extra electrical load like the brake lights, rear defroster and sends a signal to the ECU to idle up the engine.

Check your throttle plate, if it's coated in tar it will cause an unstable idle. Spray some carb cleaner in the throttle area, get a old toothbrush and scrub away. Make sure you clean the back of the throttle plate as well.

Also you changed the IACV, did you check to make sure that the ports in the manifold are clear and unobstructed?