engine lights turn off-cylinder is misfiring-why

If your engine light comes on shouldn't it stay on until the problem is fixed? Mine came on a week ago Sat and the code said my No. 1 cylinder is misfiring. I am taking it in this Sat to be looked at. I have done nothing to it since the light came on. Since it came on it has stayed on. Now this morning I get in, start the car and the light is no longer on. What is up?
That means nothing at all. Some lights stay on and some don't. They still retain the code in memory. Some will shut off if the problem doesn't repeat itself for a certain number of starts but that could just mean that the system where the problem occurred hasn't been active to set a code.


Thanks, it's just wierd to me, I would figure that since mine deals with a misfire it would stay lit, but I guess not. Hope to figure out this weekend where that misfiring is occuring.