I just got my first Subaru.  It is a 2008 outback.  Shortly after buying it (used) I noticed a subtle hesitation or stutter when I am accelerating slowly.  Typically at 20 and again at 40 mph (roughly).  There is only one noise that is sometimes present.  It may have a low grown...like you hear when you are in too low of a gear.  It seams to improve as the car warms up...but does not go away.  When the car is cold, it may also shift slowly from R to D.

 

There are no warning lights present, and the dealership apparently has not found any warning codes.  I have had the fluid inspected and replace.  It was clean.  I have had the TCU flashed with no improvement.

 

Can anyone help me with this?

It's probably throttle-by-wire and that may affect how the response feels .

I know my 2008 forester def has a different feel to the throttle than the 1999. Supposed to get better gas mileage, but I don't really see that.

 

Maybe it will train itself to your driving.

maybe some fresh trans fluid would help?

 

(check ATF level while idling)

hesitation from first to second is normal on the auto. I have it as well. Not sure about your second to third gear shift though. Second on the new fluid