[roadkillrob]

Seems to be common, rough running when the battery is going bad, somehow the low voltage affects the ignition/electronics or fuel pumps/injectors enough to cause this. When the car is idling, the electronics will be getting battery voltage and if this is low, like 11 volts, it could cause something like the pulse rate of the injectors to be slow or the ignition to be a bit off. Once you get on the gas a bit, the alternator will make enough power to get voltage up over 13 where it belongs. Just a thought!