Exhaust Smoke When Shifting-????

Hey Guys,
I went to the track today for the last time this year . The wife brought the video camera so I could see how the car was running and so i could see where I can improve, apparently everywhere. I saw that everytime i hit a shift there was smoke coming out the tailpipes. i have a theory and i am hoping this is what is happening but I want your opinions. My check engine light is on because I don't have extensions for my front O2 sensors so they are pretty much useless right now. I am thinking that the smoke is just unburned fuel shooting out the tailpipes because my car thinks it has a lean condition and is shooting more fuel through the system. Oil pressure is fine and it has never burned oil before. Oil levels are fine. the car has been really hard on gas ever since the check engine light has been on. Anybody got ideas? I hope I'm right because I have spent enough cash on this car this year and I don't need to be buying a shortblock right now.