Help a Newbe, White Smoke
 

I have a 2007 1/2 Silverado; I had white smoke coming from the passenger side aft and inside of front wheel area while stopped at a stop light Friday morning. I stopped to look it appeared to be exhaust coming from the right aft of the engine area, no lights on. I latter drove the truck to the dealer; very little smoke by then. Dealer says they can find nothing wrong. The turbo has been replaced by the dealer lately; the down pipe was left loose by the dealer, took back they tightened. It has a power loss every once in awhile with no lights on. Where was the smoke coming from????

Check the codes?

No codes, no lights, dealer says everything is good. No white last couple of times I have drove it. Still seems to be a little low on power, I am now wondering if it might not be shifting correctly.

Is the truck using any coolant? At all does the smoke smell sweet or have a dieselly tinge to it?