Car feels rough when driving

If the pedal is pulsing very fast, which I am sure you know what ABS feels like when you slam on the brakes. This can be caused by the ABS wheel sensor not having the correct air gap to the reluctor ring. Check each sensor at each wheel. Sometimes rust build up can cause the sensor gap to be off slightly and that's all it takes for the ABS to kick in, The sensors each have a small screw holding them into the steering knuckle just behind the brake rotor. You can unscrew it and take it out and see if there is a rust build up in there or if something else is interfering with the sensor. Since I am assuming the ABS light is not on, because this would disable the system, the ABS is doing its job, just being activated by something at the wrong time. Visually inspect the wiring and ABS sensors. Hope this helps some.

It is a pretty sensitive system for good reason, prevent lock up.