The last 3 days my car has failed to start at times as if the battery is shot. But when I had it checked it checked fine. Alternator is putting out between 13.9 and 14.2 volts. I can let it sit overnight and the next morning it will start just fine. However, sometimes i can start it up and drive 2 or 3 miles, cut it off for 30 to 45 minutes, and it seems like the battery is dead again. Then i have to jump it off. WTH???