i had the same prob in my 92 hb witha b16a an i burped the coolant and now it idles really strong and steady..

 

Take off your air intae tube from your throttle body.... close to the throttle plate will be 2 holes... when the idle jumps up and down, close off each of those holes with your finger, one at a time. If you close the top one and your idle evens out, then youve got a IAC problem... if the bottom one makes a difference, then the FITV needs to be tightened up.
Try those 2 things, and report back here for further instructions.

-T