I 've been using manual shift mode (DS) on my 08 S coupe with Automatic Transmission. I had no problem using DS for years and recently, when i rev high in manual shift mode it changes into Automatic mode (D) itself with the gear shift put in DS mode. Anyone else had this problem? I was racing against 350Z and i got owned as the gear changed from 2nd to 3rd without me actually shifting it into 3rd gear (i was using manual shift mode) and seems like this problem is persistent as it happened every time i used DS mode since then.

 

you have a bad selenoid in your shifter.
it's an easy fix, car / trans.must be hot for you to duplicate it.
if the dealer checks when the car is cold,it won't happen.
make sure you take a tech for a ride when she's fully warmed up. There is alot of 08 autos have had this exact problem.