My 1997 Chevy Suburban is having power issues. It won't start without a jump. Then, it stays running fine, but if it is powered back off of any length of time, it won't start again and has to be jumped. I have tested the alternator...fine. I have pulled disconnected the positive battery cable, and when you run it across the post...sparks fly. I've pulled each fuse one-by-one, and the sparks still happen. What am I not thinking of? Somewhere, something is drawing current, but what? Any tips would be greatly appreciated!