I posted this by mistake in the Prius C forum. Our 2010 Prius was stored for the winter with a battery maintainer on the 12 volt battery. When the car was started, the engine fired up but made a terrible racket as it stumbled and vibrated, flexing the motor mounts. Within a few seconds it was smooth and quiet. The drive battery charge monitor looked as the same as when I parked the car (two lines from the top). The next couple times the engine was started, it stumbled for a second or so, but now is smooth and quiet as usual.
What is the reason for that stumbling vibration that I have read about in other posts? We are in So. California, where it never gets very cold and have not encountered this issue. Is this a cold climate problem or did it have something to do with longer than average period of non-operation?
