Sometimes when i try to start my car all i get is one click noise and then nothing, all i get is the sound of all the power dying and i can not start the car at all, to fix it all i have to do is open the hood and like tap on the battery, not even hard, then all the power comes back, and the car starts up right away with no problem. The problem started to happen all the time, so i changed the battery, it didnt do it at all for a long time, now it happens like once a week if that, but still annoying. I changed the negative end with a new one, have not changed the positive one yet, but what can this be, a bad ground? i noticed with the stock positive end i can not get it totally tight, it is on there but with some force you can move it. What can this be? would that cause it? there is a good connection but u can still move it if u really try.