Sorry, no idea why it would be constantly moving backwards. Could there be a joystick plugged in that perhaps isn't calibrated? Or try restarting your machine and make sure there's nothing pressing down on your keyboard, and there are no stuck keys.
Defo No Stuck keys as restarted machine etc. Even unplugged and replugged the USB keyboard and retried. All. Games are fine except this one? Which is strange. I have Got a g29 wheel Connected but had no buttons pressed or stuck in anywhere. I'll try unplugging that and see as I didn't think of that
edit: still strangly stuck moving backwords? this is very odd and cant find anyone else with this issue :/