Create a new 'model' in the memories and reset everything in it to default. Reset the ESC back to defaults and rebind the receiver.
Now start fiddling about. On a couple of ESC's I've had the end points for the throttle needed adjusting as full was reached at about 70% of full travel.
Were you using the same motor/ESC combo before?
Xray T4'16, T4'14 (Wet Car)
Xray X12 2016
wlrc.co.uk (West London Racing Centre)