GMC Repair: ABS brakes-1997 GMC Sierra, gmc sierra, abs brakes

Question
1997 GMC Sierra-extended cab:  ABS is activated at low speeds, such as when slowing down, or cruising slowly (easing forward in traffic for example). You can hear the chattering of the ABS, the pedal gets stiff, and truck does not want to stop.  You must quickly take foot off brakes, and reappy to stop. The truck has been put on 2 diagnostic machines, both said there were no problems with the braking system.  Any ideas?

Answer
hello carrie
you do have a problem and this a abs senser have it changed and you should be fine i dont care what they tell u have heard of this more than once . tell to pull the wire to senser for abs and then see if it does it good luck to u hun and you have a pretty name pete