2000 ford f250 acceleration problems?

[Tim H]

I have a 2000 f250 2wd 4r100 trans, I live in arizona so its not like it get to cold in the mornings, but the last two days on my way to work when i get off the gas coming to a light or stopping in traffic then get back on the gas it doesnt go any where, truck still stays at normal idle but when you press the gas rpm's dont change or anything then it will decided to work again. so i have to keep it thottled up alittle when i got to stops. after work it doesnt do it. I know i have to replace the trans cause the clutch disks are worn out and it slipping. Is this from the transmission going out or just a sensor