1984 fiero high idle (Page 1/1) cartercarbaficionado NOV 17, 09:47 PM so i decided to help someone work on their 84 iron duke and went through most of the steps to get the idle back to normal and i did suceed. until while he was driving it went back to a 2500 rpm idle. still no vaccum leaks or codes to speak of other than it set the speed sensor code and we havent figured out why just yet since it only did it once the fiero im working on has been on the forums before and nothing was solved but apparantly if you look at it in person you spot alot of sensors that sure arent the right ones from a previous owner, i have replaced all of those so im not quite sure what else it could be