I have a 99 xlt 4x4 4.0 the abs brakes had been pulsing occasionally when coming to a complete stop so I replaced the left front wheel sensor, now the abs will occasionally pulse at speeds less 20 mph and is difficult to come to full stop. it will do this for several miles and brake applications then ABS light will come on and will work normal.

 

Are you sure its an ABS Pulse in the pedal and not a warped front rotor?

Use an OBD2 reader that can read ABS codes and display sensor pulses while driving
Guessing at ABS issues will cost you a lot more money than a good Code Reader, and code reader can be used on ANY 1996 or later vehicle sold in US/Canada, not a Ranger or even a Ford thing, ANY Vehicle
I got a BlueDriver a few years back, Bluetooth OBD2 reader, no complaints and not too expensive

Example of the "B" and "C" ABS codes here: https://www.fixya.com/uploads/images/d719fdc.gif
And here: https://www.troublecodes.net/ccodes/

 

This is an intermittent issue, A warped rotor wouldn't be intermittent. I'll see if I can get a code reader. Thanks.