Cadillac Repair: driveability, intermitant, check engine light

Question
THIS 4.6 HAS AN INTERMITANT MISS,ENGINE SURGES AND STARTS HARD IN THE MORNING WHAT COULD BE CAUSING THIS PROBLEM?

Answer
IS or HAS the CHECK ENGINE light ever illuminated while driving the vehicle and or has any other lights illuminated or any messages from the message display center ?.

What work or diagnostics of ANYKIND WHAT-SO-EVER have been performed on the vehicle trying to fix this problem ?.