2000 Chevy Silverado Start-up idle speed

When starting on a cold morning my engine idles very rough (high to low surging) almost to the point of shutting down. I will use the foot pedal to maintain ~1500 rpm for a minute or so until the engine maintains idle on it's own. After beginning the trip the engine runs fine. The truck has been running fine since purchasing new. I gave it an engine tune last year. Thanks for your help.
Dan