This is my commuter vehicle, the milage is 159K, this car has ran flawless in the ten years since i've had it, it has been well maintained.<br />I got home from work last evening and prior to switching off the motor, i noticed that at idle it was running at 2300 RPM, WOW! this has never happened before.<br />Upon starting it this morning the RPM was the same, after the engine warmed up it started to rev back and forth, kinda like "vroom! vroom! vroom!. <br />Can anyone explain to me what is this a symtom of and what caused this to occur.