* The closest you might be thinking of is Bumblebee. While Bumblebee is primarily yellow, he has green accents on his car form, and in the movie, he does temporarily have a green camouflage paint job.
* However, there are no green-colored Autobots or Decepticons that transform into race cars in Transformers 3.
It's possible you might be thinking of another Transformers movie or another piece of media altogether.
