I too had the same problem. I changed the OVP and that didn't do it. I cleaned the Idle valve and that did't do it either although it is a good idea to do a through cleaning of this valve. I even re-soldered the joints in the idle control module. That worked for a short time. Finally I bit the bullet and ordered a new module. That cured the problem. My guess is that you too will need a new idle speed control module. E-mail me if you need a good source.