1999 Mustang power seat rocks on acceleration

I just purchased a 1999 Mustang with a power drivers seat. The seat rocks back on acceleration which has become quite annoying. There is a nut on the left side of a pivot that rotates with the threads but it is tightened so thats about all i can see that can be adjusted. Does anyone out there know what the problem is and if it can be fixed without replacing the entire track?