2005 Pontiac Grand Prix Starting / Idleing Problems

I own a 2005 Pontiac Grand Prix GT with the 3.8L V6. Recently I have had a problem with the engine dieing on start-up. It usually happens when the engine is already warm-Doesn't happen when first started in the morning. I have to give it a little gas to keep it from dieing and then it is OK. I also have noticed that it sometimes will run poorly(sluggish and erractic acceleration). If I turn off the engine and re-start, it runs perfectly.

Is this an electrical issue or computer related? I have done an ODB II scan and nothing comes up.