2003 mustang shifter issues

Tonight the shifter would not activate proper
gears. It appeared the cable or linkage broke.
However, at the shifter I shook the cable & it
started working. After I worked thru from park to
other gears, it again felt as if something was broke.
As you shift slower, the gears engage but at time
not where shown on shifter. This is a v-6
automatic. When you can find drive, transmission
operates properly.