update: the check engine light in my car is now on some days and off other days. i know i have a minor exhaust leak at the engine head on one side, but i am not willing to pursue it if that minor item is the cause of the fault code. since my car passed emissions testing last month i am confident i have nothing to worry about when my check engine light is on!
truth be known i have always despised "idiot lights" and curse the engineer who thought of them AND overall passenger car emission control systems (this means alot since i am an engineer). there are obviously far too many (typically minor) things that can be wrong with an emission control system, but regardless of whether the problem is a 1 of 10 on the "trouble scale" or a 10 of 10 on the "trouble scale" as a driver the only indication we get is an idiot (check engine) light! NOT COOL!!!
thanks for letting me rant and rave