Your transmission is downshifting you - for whatever reason.

To test this, move from "D" to "3".
Drive around in "3" and see if the problem is noticeable.
This lets the highest gear be only 3rd and no torque convertor lock allowed.

If it still acts up in "3"
then move the shift lever to "2"
and try that.
"2" Restricts you to shifting between first and 2nd.

If the problem is still in "2" then
lock it in first gear in "1".

"1" keeps you in first gear no matter what. (supposedly).

If there is still a problem then it is not the transmission changing gears.

You might keep it in "1" and the push on the gas and let it up and note any clanks or clunks.

Please let us know what this test tells you.

 

Also - make note of the Sport mode and the normal mode.
Sport mode will aggressively downshift - I would think.
The button for sport and normal is toward the cubby box and the "1" part of the shifter legend.

 

Sounds good jfall, thanks for the info. SO if the tranny is not the prob then what would it be.

Oh, and I did find out about the sport mode. I saw the green light on the dash and found that my dog had pushed it....