My Buick recently started dying while idling, and more recently the car has started dying right when I remove my foot from the gas. Also, my battery guage reads below the mid-point some mornings, and the car will not start, or it will start and begin to rumble and then will die. If I floor the gas while the car is trying to start and doing the rumbling, sometimes the battery guage will kick in and start to rise, and the car will then normalize.
I have replaced: battery, fuel filter, relay
I have had my alternator tested and it is working well.