may 4 2011 I purchased a new mazda3 hatchback 2L automatic. From the beginning I noticed that under acceleration a white or at least very light emission was visible from the tailpipe,but never at idle. It does not matter if it is cold out or a hot day, it is constant. When cold out it begins at once,but in warm or hot weather it does not begin until engine is warmed up.Also after any drive I detect an odor of sulpher,so I think this is related to the emission system. The dealership says no and that everything is fine. I checked with other sources including other dealerships and parts suppliers and was told by most the first thing would be to check for a malfunction with the catalytic converter.What do I do now? I am frequently asked by drivers who were behind my car if it is burning oil.