My Rendezvous does the same thing. I read that if it goes away when the car warms up, then don’t worry about it, but mine drips a lot of water out of the tail pipe to the point there is a puddle under it. Are you loosing coolant (do you need to add it more than occasionally)? If yes, you have a seal leaking. Has the car been tuned-up recently? An out-of-tune engine will burn fuel inefficiently producing smoke / odor and may be more pronounced when first starting the car.