i thought about that so when it did it i pulled off the road and popped the hood and the fans were not spinningAny type of electrical load will cause the car to idle faster as the Alternator takes up the load. If the engine fan kicks on this will impact idle speed. If you turn on any heavy power consuming device the idle will jump.
Any defrost settings will jump the idle.
Could.yep up to temp. would a failing battery cause it??