My 2004 2WD 4runner seems to behave strangely when braking.
Every so often when I hit the brakes on the highway or on the side streets my foot will feel a kick-back on the pedal. It's the same feeling as when the ABS brakes are activated but it is only one pulse. It will sometimes do this when I am at a complete stop as well.
Also, the other day I was stopped on a steep hill. When I let go of the brake the car started to slide backwards and the Hill-Assist buzzer went off but the truck still kept sliding back. Then the ABS kicked in and the brakes started to pulse but the truck did not stop.
On another occasion, same hill, the buzzer sounded and then I heard a sickening crunch eminating from the rear of the vehicle. I thought I hit the person behind me but my truck was still sliding backwards.
Has onyone successfully used the hill-assist and what should it feel like?

I'd take it to dealer based on that description.

Well I took it to the dealer.
They replaced the master cylinder and now the HAC is working fine.
If only I can get rid of this wierd popping that happens on the brake pedal once in a while.
There seems to be no rhyme or reason to it.
It's very annoying.