the engine is doing this weird fast then slow then fast then slow idle when in park. Also, after driving and turning off the engine (like to fuel up), when I try to restart the car it refuses to start until it has cooled off some -- ususally 20 minutes or so. That's very inconvenient. We have replaced the " idle air control valve" but that didn't help the problem. I see where you have recommended to others to check the " fast idle valve". Is that something different?