wheel drive pin
You might want to check the drive pins that go through the axles and into the back of the wheels. They are common to break with lots of motor and when it does if the wheel is tight it will have some drive with friction but under hard axccelleration it will do circles. If you set the car on a bench and hold bolth tires give it a LITTLE gas and watch for one of the axles to spin while holding the tires. If one spins that is the culprate.