possible coil pack problem?

Out of the blue, my 04 Cavalier, 2.2 ecotech, started with a lot of white smoke and running real rough with loss of power. I've been told it could be the coil pack but not sure I want to spend $90 for part that may not be it. Any ideas about what else it might be? Engine light scans don't seem to give definitive answers.

Out of the blue, my 04 Cavalier, 2.2 ecotech, started with a lot of white smoke and running real rough with loss of power. I've been told it could be the coil pack but not sure I want to spend $90 for part that may not be it. Any ideas about what else it might be? Engine light scans don't seem to give definitive answers.

White smoke means it's burning coolant. The coil assembly could be bad, but wouldn't make smoke. I also have an '04, and a month or two ago the ignition module went out causing a p0300 and the symptoms you describe (minus the smoke). What codes does yours have, and why doesn't it give a definitive answer?