After the engine warms up, the car's computer lowers the rev's. When this happens, the car starts to "bounce" around 600rpm. It causes vibration and could become a big problem in the future. If anyone can help me diagnose my car, I will be very much obliged. Also, there is no check engine light on, so I can't diagnose that way.
1999, Nissan, Maxima, idle, engine