Car dies when idling? Gets worse the colder it gets... Any ideas?

Its a 2004 Ford Taurus with 125,000 miles. The check engine light is always on and by always I mean always. The car normally runs great, however on colder mornings it will not idle. It runs a little rough on these mornings too, a little delay after hitting the gas peddle before it'll speed up and when I stop at Stop lights for long periods I have to shift to neutral and it barely stays running. If I stay in drive it will die.

On warmer mornings now that we are getting into Spring it runs like a champ, no idle problems no delay it does not run "rough" at all. It passed emissions but they told us that Mass Air Flow Sensor needed to be replaced. We did so thinking that would solve the problem and the Check Engine Light is still on and it has made no difference in how well the car runs...

I had this issue before with a previous car in which the Fuel Filter and Cat. Converters needed replacing but that car ran very rich and would not exceed 3500 rpm's period (made highway driving difficult for a week). Neither symptom is present in the current situation.