Originally Posted by mrbell83
It was flashing for awhile then it stayed on.
A flashing SES light is according to GM a "potential catalyst damaging condition" aka usually a misfire. Misfires are typically a car in need of a tune up. Afterall the owners manual etc doesn't suggest a tune up unitl after 100K.
It could be anything, it'* most commonly a coil pack, plug or plug wire. If they appear new, I'd wonder about the LIM gasket, although I've never seen one cause an issue.