I'm the original owner of this Scion xB and this problem has always been with this vehicle. When I do even a very slow acceleration from stop on level surface with a slightly wet conditions, or slightly inclined slope, the front tires break traction and the vehicle can lose control. It seems the front end of the vehicle is too light for the front wheel drive. I think this is a major design flaw with the 2004 Scion xB. After all these years and knowing this can happen I've been able to anticipate this problem and compensate by driving proactively and taking extra caution on start. This problem also occurs occasionally when the vehicle is in motion and I need to accelerate as in merging with traffic on a sloping or slightly wet on-ramp.