Automatic transmission having a hard time going after stop light?

2001 ford escord I will be on a stop light then try to go but the engine just revs, I have to put it on L for it to go other wise it won't go.
Automatic transmission
If the transmission fluid is good, what else can it be?

Take it to the shop trying to guess is a waste of time and money

Pump failing in the transmission probably if the fluid is in the correct fill level - time for a tranny overhaul - probably cost more than the vehicle is worth - unfortunately.

Could be due to low fluid pressure problems, clogged filter, faulty or clogged shift solenoids or other issues with worn friction parts like clutches… Does the fluid smell like burned toast? Or see specs of metal in the fluid? That could indicate trans overheating and/or worn parts. Has the filter been changed? Old fluid flushed out? A shop would have to test fluid pressures and proper solenoid operation and check for excessive wear/material in the pan and try to better diagnose what the issue may be. Given the age, it may be due for a new /used trans or overhaul.

Insufficient Input from Vehicle Speed Sensor Automatic transmission having a hard time going after stop light - 1

You need to replace the fluid and filter first, and quick, before you cook the whole unit.

Torque converter is pretty common in a Ford Tarus anyway, do not know if it is the same kind or not but simptums pretty much the same thing.