I'm only guessing you have the AOD trans.  That vintage had
a plastic connector bushing to connecth the trans throttle
pressure cable to the throttle linkage at the engine.  They
tended to wear out and break frequently as the miles went
up.  They have a brass replacement bushing that is fairly
inexpensive and easy to replace if you have a couple of
basic tools and a little patience.  If this is the problem,
it needs to be replaced ASAP as this cable controls line
pressure in the trans.  With a bad bushing, the trans
operates at low pressure and slips the clutches resulting in
failure in a matter of a few miles if it is driven hard.
The adjustment of the cable is also critical.  You should be
able to find instructions for your vehicle in a public
library shop manual.  Some places like Autozone have much of
this info online at their sites.  Check that and get back
with a bit more info on your vehicle.  Someone here will
probably be able to help and guide you but, info is needed.

Lugnut

have you done the simple task of changing the tranny fluid...... these
crown vic trannys are funny that way