I"m having an issue with one of my Gen2 RS esc's I use in my T5m. For the last several months ( I don't run this truck that often) I have noticed that the truck didn't seem as fast as it once was. I also noticed that I had a lot less brake than I once did. I went from a 10.5 to an 8.5 thinking it was the motor. I also upgraded the FW to 255 in the ESC, checked to make sure the current limiter was not on and recalibrated the throttle many times. It all just seemed really soft. Yesterday I decided to drop an old black case RS in the truck and it was all back to the way I once remembered it....very fast and LOTS of brakes.
So is my Gen2 just busted?
From first blush it sounds like maybe your sensor system isn't working properly. The RS and RS Gen2 have sensor testing functions built into them so I'd suggest putting the Gen2 back in and begin testing the system.