What else could it be? I have a 92 pontiac sunbird 4 cyl but it wont start, I have replaced the ECM, the distributor module, plug wires, and crank-shaft sensor. while cranking it only fires on 2 cylinders 1&4 middle 2 does not fire. please help. If somebody knows oof something I have not checked please send info on how to start my car. thanks.