I think I may have experienced something similar when I had my 12 SHO. I would do a throttle pedal relearn. To me it would seem as if using the car in the same tp range daily it would just get used to work in that zone. To my butt Dyno the car would be quicker to downshift and shift better after the procedure. Use the search feature on this it's been discussed here before.
Sent from my iPhone using Tapatalk