Vehicle Dies While Coming to a Stop or while Starting to Move forward/reverse

I have an automatic 2004 Ford Excursion 4WD and with a Triton V10. I am getting a code that says the "output sensor circuit malfunction".

Let me describe the problem in detail:
While driving the Overdrive Light on the shifter starts to flash and at this point if you slow the vehicle down too much it dies (kind of like letting off the clutch to much on a manual vehicle) It will start right back up but as soon as you engage the transmission you have to basically floor the gas pedal so that it will not die on you. It does this in reverse and in drive, however in park it idles fine. This problem happens more frequently and much quicker if we are pulling a trailer.

Is it just the Output Speed Sensor or the Output Speed Shaft Sensor or both or something else? Please help!