I too have a 2004 Hyundai Santa Fe 4CL and twice the engine has powered off for no reason; once at a stop light and the other driving about 10mph. Since no check engine light is showing the mechanics can't pin point the problem. The engine has revved up while idle and driving on the hwy. Scary since I drive 66 miles RT each day to work. If this has happened to you please let me know how you fixed and if the problems have ceased. Thanks!