Idle. And loss of power while driving and engine still on.

1-starting the idle is not normal it stays hi (swinging revs 2500 to 3100).
2-While driving (shaft on D Position) the engine sound goes hi (as if the gas peddle is pressed) the sound goes down (but still hi idle). Then
3-The car slows down to zero speed during that pressing on gas give no power to the car only the engine
respond. The shaft is still on D Position.
4- So the car stops, the engine still on (with hi idle) To move on the car, the engine must switch off and on again. The same repeats over again.
5- the above happens only when shaft on D. But not on 1 position.
6 the question is this an engine issue or a transmission issue?
Note : the TSP is completely renewed but still getting error massages of PO123 and PO222