Hi My tach went out. It was working and from time to time it would start jumping around and then work again for a while but now its completely out. I tried moving the wires around the coil which that use to seem to work but not anymore. the wires around the coil don't look like theres any breaks. I not much of a electrical diagnosis person so any help where to start would help. I have a GM manual but kind of difficult to follow steps. Thanks.