I have a 2000 3.0 auto 4x4 ranger which has the abs option. Sometimes it will randomly have the breaks start, well, pulsing for lack of a better term. I'm not talking the brake pedal pulsing like the abs is doing it's thing though. At low speeds the breaks will grab and then loosen without me even touching the breaks, it seems like about once maybe twice a rotation they basically pulse. They will keep doing that until I either floor the breaks with a little bit of speed or go above probably 30. Has anyone had this happen and or have a solution to it?

 

First thing I would check is the ABS tone rings and wheel sensors. If the tone ring is missing teeth on one side or has a bad sensor the ABS might interpret that as one of the wheels skidding and activate the ABS pump. Im basically just spit balling here though...

 

Sounds like brake rotors are slightly warped.