I have a 550 xp auto tune that would die everytime I would take my finger off the throttle and then try to throttle up again. Today we had ArborMaster come to our location for fours days of training. I tell one of the guys my issues. He shows us how to "reset or retrain" the auto tune.
He took about a 10' bolt and starts ripping with the grain for at least 90 seconds at full throttle. You can hear the saw make a few coughs, hiccups whatever you want to call them. By the end of the 90 seconds the saw is running smoothly. It ran like a champ the rest of the day, it never died!
Full throttle in some wood for 90 seconds that is the key. Give it a try before tearing into the carb.