Every morning when I leave for work after I drive for less than a mile to the closest stop light my car seems like it coughs. While at a complete stop my car will "cough" RPMs will jump from 1000 to about 2000 for a split second and drop back down to idle. Why is it doing this? I don't warm up my car, I just start it up and back it out. When I leave the house it is usually not that cold probably low to mid 40s. It only coughs in the morning. What gives? Any input would be greatly appreciated. Should I warm up my car? Take it to the dealer?