1993 corvette after setting 5 days runs rough for 5 miles then runs good what could this be

When last did you change your fuel filter or change your air filter and if the check engine light come on check it right away that would avoid the guessing, and check your vacuum hoses when the engine get warm they may get soft and sag down and if it have any cracks that could cause a vacuum leak

Runs fine when it is warm so it has to be something with a cold starting engine having to do with air, fuel mixture, not being right for cold engine. Could also be an ECM issue.