I reported this issue during the Closed Beta, too, but it is still happening. Opening screen racing to the "Start" line to begin the initial auto race; my car is "racing" along just fine. As soon as I cross the "Start" line using full-throttle, (XBox controller "Recon Tech" model), my car comes to a screeching halt and begins spinning the tires, as if I am power-braking. When I release the throttle, the cars "shifts" into Reverse and runs at full throttle. Boost is even available at this point. When I apply reverse-throttle, the car accelerates in reverse. When I apply full forward throttle, the automatic transmission "shifts" into "1", comes to a complete halt, and performs the power-braking, previously mentioned.
At this point, the game became unplayable for me.
Craig "IDMooseMan" Peters
Nampa, ID, USA