mate, give mooony's & my wire setup a go, u never know...
Try fiddeling with the throttle curve, also are you using drag brake, because too much can also cause cogging.
Have you hardwired the motor to the esc, or are you still using bullet connectors?
have a tamper with the motors timing on the can, your vortex should have come with instructions that show you how to do it, etc...