have you checked for airleaks in the engine? if it hasn't been running for a while, it could have worn out o rings. if you have been using it regularly, it's probably an issue with tune...although in saying this, back when i was racing a few years ago i saw a few engines run (when hot) unstable on AT or sound very "pingy" when coming into the pits during race conditions. Maybe things have changed with AT, but that's something i remember about it...it could also be a lot of people were just not tuning the engines right though.

richen up the top end if it is bogging down out of corners after being ont he throttle, and richen the bottom end up a little as well.

if none of this works, go back to factory settings and tune it from here.