2 Questions first. 1) How many miles are on the car? 2) Did it just recently turn cold where you are?
It sounds like 1 of 2 things. o2 Sensors or Intake Manifold Gasket. There is a Vacuum leak in the IMG that when the weather is cold gets exposed. The cold contracts the gasket opening up the leak. This causes rough running until the engine warms up and the heat expands the gasket closing the leak - allowing the engine computer adjust the engine to run normally. - JT