well, mine has been working fine for 2 years now. I havent ran it for a few months so today i go to start it and nothing.. No spark. I tried my spare GM module and also my other GM coil and still nothing. I have power to the module and coil but it just wont fire the plugs...? Not sure what is wrong. was working fine last time i drove it..
Ground at the module is important too. The module pulls the coil - to ground too charge coil. It also needs trigger signal from pickup coil. The pickup connectors can be troublesome.