After doing all the common checks to figure out why my idle was having the ever so common fluctuation problem between 700 and 1500 rpm's, I discovered that the cause of the problem was my AEM alternator pulleys. The different pulley sizes caused the alternator to spin at a lower speed which did not put out the voltage that it was intended to put out. In order to produce the necessary voltage for operation, my ECM was kicking up the idle to a point higher than needed and then cycling back down and then back and forth continuously. Just thought I'd let everyone know in case they have had similar problems.

 

hmm thats some interesting stuff,

i think the hot idle for the prelude at its very lowest can be 550 maybe a bit higher, and with the aem under drive pulleys that would do what you described