Why would the coil packs seem to keep going bad on a 1999 Cavalier within 4 months of being replaced?

Answer 1

The coil packs might have gooton water in them or on them. If you have a warrantee, which most coil packs come with, just take them back and get replacements. When you put the new ones on, use some terminal compound around the seal of the new terminals. Make sure not to get it on the metal contacts themselves. The function of the coil packs is to deliver voltage through the plug wires, to the plugs so that they can fire at the proper time. If the plugs or the wires are old and have built up resistance, this flow of electricity is diminished or interrupted. Electicity will always take the path of least resistance. So, if the plug wires become broken or they are shorting to each other or ground, they can cause the problem. The coil pack will not be able to overcome the resistance of the wires or the plugs and they will just short circuit and fire back through themselves to ground. This will kill the packs and replacement is necessary. Best fix is to replace the plug wires and plugs. That is where I would start in trying to fix this problem...Hope this helps..