Honda Repair: Surging Idle, air control valve, radiator fluid

Question
I have a 90' Prelude with a B20A5 engine and a B21A1 throttle body. The problem is that the idle keeps surging up and down between 8rpm and 2,000 rpm while at a stop. (at driving speeds the car's fine) I have replaced the fast idle valve, fuel filter, and adjusted the throttle cable and messed with the idle screw. I have also checked for vaccum leaks and found none. I don't know what else to do! Could it be the IACV (idle control valve)? If so then how do you check to see if that is operating proberly? At wits end...
Lee  

Answer
IT SOUNDS LIKE IT IS THE IDLE AIR CONTROL VALVE THERE REALLY IS NOT ANY WAY TO CHECK IF ITS OK OR NOT I JUST GOT MINE AT A JUNKYARD FOR REALLY CHEAP AND WORKS GREAT BECAUSE MY IDLE WOULD ALSO BE JUMPING LIKE YOURS I JUST REPLACED THAT AND IT WENT AWAY BUT IT CAN ALSO BE VERY LOW RADIATOR FLUID SO CHECK THAT ALSO.