2000 Dodge Dakota Dadge Pickup Truck Stallingout Tempature 30 S Get Check

I have a 2000 Dadge dakota pickup truck. It is stallingout when the tempature is the 30's. I do not get any check engine lights on the dash. It will stay running after it warms up. This problem started about Oct. Any ideas as to what the problem is or what to check. Ive used an injector additive in the fuel and use shell oil fuel.