Pontiac Repair: White Smoke, o2 sensors, head gasket

Question
I have a 97 pontiac grand am se 3.1 v6 And everytime the car reaches running temp and I am at idle or sitting at a light, white smoke trickles out of the tail pipe but clears up once I start moving.  I have changed the upstream and downstream o2 sensors and the egr valve.  What else could the problem be?

Answer
hi Delonte:

Well it's 1 of 2 things. white smoke is not good if it has a sweet smell to it. If that were the case the engine is buring coolant. And that is NOT a good thing it could be a head gasket,lower intake gasket or cracked head/engine block. All BAD! is the engine low on coolant?  The other possibility is that ther  is nothing wrong with it. A by product of complete combustion is water. If you live in a very humid or cool climate or both you could see this more often than say someone who lives in Navada where you wouldn't see it hardly at all. Hope fully is the later and there is nothing wrong.