I have an LRP Sphere TC Spec with some history (I had it and it worked but the set up button went on it so I sent it to Associated and they fixed the setup button, the put a new cap and new rx wire on it and tested it saying it worked) I bought a used 21.5 Trinity High Velocity motor and that's the only sensored motor I have so I can't test the esc with a different motor.

When I advance the throttle, the motor squeaks a little, shutters, vibrates, and sometimes spins a little. It seems like it's not getting enough juice. IF I spin the wheels (like a kick start LOL) the motor runs and works as long as I don't drop the throttle to zero.

Any ideas what this could be, is it the motor or the esc? Any way I can test the esc with a multimeter?

Thanks in advance.