to go more in depth of a bad IACV... the car will typically have turrets, meaning it will rev up to like 2500 and then back down to the regular idle range, then back up again and repeat until your putting load onto it. If this is your problem, to save yourself a costly part right off the get, you can clean it by simple taking out the three 12-mm bolts and spraying carb. cleaner inside it to clean all the carbon buildup out. Just keep spraying it until the fluid coming out isn't black. Then tighten the donut inside your Fast Idle Control Valve... seeing how they tend to come loose inside on occasion.