I just noticed, but I barely drive my Integra.
The idle is fine (700-800) when my headlights are off(day driving), but when I was doing some night driving(headlights on), idle would not come down (1100), is this normal as I didnt remember my Integra doing this before??
Also, I noticed that when I turn on my rear window defogger the idle jumps to 11oo rpm also, but that is something different.

 

When you are putting an electrical load on your charging system the ecu increases idle command to compensate for additional alternator load. It could be possible that your battery is not accepting the charge or your alternator is unable to produce enough current, or there may be nothing wrong at all. I wouldn't be too concerned as the increased idle speed helps maintain the battery's state of charge.

 

Yea get a volt meter and do some recon on you electrical system. Did you install some new stereo components. Take the negative battery cable off while running if it goes off,, alternator is going. But if nothing new install in the last few months, check for wire burns, or may hes right, the voltage regulator is going bad. Check ya ground wires also. if you have a some kind a of ignition performance stuff check those wires also. Hope its just the alternator, man wiring in a bitch, later