My jeep grand cherokee with engine 4.0l mfi will start from a little below 12v and driving for a little less than an hour the voltmeter reading on the dash begins to drop down rapidly to 9v depending on the outside temperature.When really cold, the drop is slower than when hot and then it starts to stall and the check light comes on and stay lit untill i turn the car off.A battery test proved ok and the alternator seem fine.when parked for a while, it will start fine between 9 and 12v again depending on the temperature outside.Is it the battery, battery cables, alternator? Just a little background, the engine was replaced with a similar 4.0l mfi and since then it has been acting this way with the power always dropping even with a new battery.can somebody please, let me know what might be the problem and how i can repair it. Thanks.
Apr 26, 2007 at 2:27 PM