1999 rx300 swaying in rear when going 40+ mph and holding gas paddle. Feels like stability control/abs is kicking every about 2 secs in on rear left of right wheel and making the car sway left/right. Imaging someone in the trunk trying to shaking the car with their wight left, right, left, right.... Does it for like 30 seconds, then it stops and the car drives fine, then it starts again randomly for another 30 seconds or so and stops again. Its almost like the stability control is trying to adjust the cars direction by applying break to ONLY one of the rear wheels at 2 second intervals. I did the zero point calibration but no traction control lights come on the dash when doing it so I'm not even sure if it was done right.

No lights on the dash btw. Engine, ABS and traction lights are all OFF.

Anyone have any idea what this could be? I'm not even sure if my car has stability control, its a 1999 RX300