I have a 2003 Chevy Cavalier. I just put a motor in it that only has 55,000 miles on it and I bought a used alternator and battery. I had the alternator tested and it was good, it put out the right voltage. However, I have to jump my car to start it every time still and when you jump it it will only run for about a minute once the cables are unhooked and then it will die. Also, as soon as the cables come off the battery light comes on. What could be the problem?