93 prelude idle problems

i'm having troubles with my idle on my 93 prelude 2.3 litre, cold air intake and header. when i alow it to idle under 1800 rpm, the idle goes up and down, why is this happening? thanks scott

possible iacv sticking open and or closed aka idle air control valve

yeah...happens only before the tstat opens right? every honda ever made has had this problem at one time or another. IACV acting up. the reason it doesnt do it after the car is warm is because the CPU stops getting info from it when the car is warm.