ok so my lights and everything was pulsing in my car. i changed all the grounds checks the wires and even put brand new ground cables recharged my battery. car worked fine for about a day then i drove it a week later it started pulsing even harder the the point were my cd player was turning on and off and car was studdering on the road then the battery ran out and now my water pump is leaking. is it the alt? what else should i check before replacing the alt. could it be the ecu?