Yesterday me and my friend were on a cruise on the highway him in his 07 impala SS and me in my MS6 and we were doing WOT runs for s**** and giggles and just cruisin around. When we stop and got out he told me a couple of times that he saw a little puff of smoke when i shifted. he specifically said that it wasnt too thick but was noticable. So what does this mean?? is it anything serious?? also because of this happening is there any other symptoms that i should be on the look out for in the future?? thanks.