Cold Start Problem

I recently purchased a '95 Town Car Cartier edition with only 51,000 miles on it. Engine and transmission have checked out perfect except for one thing. When trying to do a cold start (55 degree ambient temp) I have to have my foot partially on the accelerator as the engine won't stay running on it's own. This morning it acted like an old carburetor type engine that was loading up for a few seconds before smoothing out. After warming up I have no other troubles. Would a tune up help ? I'm not really sure when the vehicle last had one. It runs flawlessly otherwise, mpg is OK as well. Thanks in advance....