It a 13/16 size nut that will not move at all. Tried impact wrench , and will not move

Can't get the rear shock lower nut off to replace shock

Try spraying PB Blaster on the nut, allowing it to sit for awhile, and then spraying it again. Other ideas are to use a 1/2-inch drive, 25-inch breaker bar ($10, Harbor Freight) and, if necessary, apply heat to the nut.

What's the rating (i.e. ft.-lbs of torque) of your impact wrench in reverse? With the proper size metric socket, your impact wrench may get it off. All fasteners on your Taurus are metric.