Depending on the manufacturers presets for arming (ac config and alt), it will advance thrust to GA and command the FD to climb on current heading.
TOGA will not engage until below 2000' RA, so with your scenario at 3000'...
Depending on the airport, you may not want to do this. This may not keep you in compliance with the missed approach procedure and routing. (ie continue descent to the MDA/DA...etc)