Sluggish Gear Change in STX550

[MattLon]

Hi all, Im new to the forum. I have a 2011 STX550. Ive notice the auto transmission is getting sluggish to change and I often have to press the accelerator or use manual mode to get the transmission drop a gear when in general traffic speed. It keeps trying to use the motor torque instead of changing gear. If anyone has any ideas it would be appreciated.
Cheers
Matt

 

[Old.Tony]

Is it like gone to "Economy" mode instead of "Sport" mode?

 

[Olpha]

These units are notorious for being "lazy". I often find mine doing the same, yet after towing the caravan it seems to become a gazelle.
I'm not ashamed to admit to giving some unsuspecting Hilux or Ranger a bit of a surprise off the lights just to remind the electrickery circuits what they are meant to be concentrating on.
If by chance (quite possible) that this doesn't help, it might indicate a BCM (boost control module) issue (also common). If you notice that nothing is really happening until you get above 2000 rpm and then it starts to get stuck in, check the BCM.