As preventative maintenance, I just replaced my three-year-old factory plugs with same. The old plugs actually looked very good. After the new plugs were installed, when I started the car it started hunting all over for an idle. Restarted it and it seems to have gone away.
Are these computers sophisticated enough to know the difference between new and old plugs and re-adapt to a better or different spark? Either that or maybe I disturbed a vacuum line as I was replacing the plugs.