Well, I have been reading lately how many of us are having problems with a studdering in cold weather just after startup. I too had the problem. After most people thought it was a fuel problem or timing I thought about how long it has been since I changed the fuel filter/water separator. Well I looked it up and found it was a little over 40,000 miles ago. Changed it out and it runs fine in the cold. It always ran fine when warm. I decided to cut it open to see just how bad it was. The pleating was completely black. Nothing stuck in between the pleates but still bad. Always check the simple thing first.