same issue with my 1999 vti, what i did it sa sobrang inis kona, after ko bumili ng brandnew original IACV sa Casa (cost 6800) ay binaklas ko yung IACV, Throttle Body, buong intake then 2 cans of carb cleaner then nilinis ko ng bonga bonga tapos let it dry for 5 to 10 minutes then put it back together then walah!!!

heaven!!! eversince hinde nako nagka problem sa idling..2 years na nakaraan..

HTH