Do you have, or know someone who has, a Tactrix cable? Seeing a data log would be invaluable. Are there any bright metallic specks on the plugs? Your picture is not good enough to verify.
Originally Posted by canis
It's done it through more than one tank of gas (different brands) and a bottle of Lucas injector cleaner. No real noticeable symptoms. Just a slight, erratic tick in the idle, but I may be dreaming things. Overall the car drives fairly normal. The most consistent thing about when the light comes on is when its below 50*. The spark plugs I pulled out (in the pic) only have about 7k on them. I just replaced them last spring.