I have the Akron. Slightly different beast but I don't have troubles out of mine (stupidity caused drippin's fires aside here.)
My thoughts on what might be the issue.
1) Wood chips not soaked or not soaked long enough. (chunks are soaked 1 hour)
2) Kamados are very odd beasts at low temps. My Akorn to stay at 225-250 I have to crack the top vent a tiny bit (.5-.75 per the Akron's guage.) and the bottom is closed.
*)Some people suggest running the top wide open the only time my akron says to do that is when smoking/cooking poultry and then you regulate with the bottom but you are at 350 so you need the air. Or for high temp broiling.
3) You want to come to temp when smoking with the vents (open the vents to regulate the air from the first moment) don't drop a weber cube in the pit and let it start in the open air because it will light way too much. Kamados are not forgiving beasts when you over shoot.
4) Check air leaks, my understanding it that Kamado Joes are pretty tight out of the box. Did you scorch a seal that is allowing air in?
Best of luck!
Current Smoker: Char-Griller Kamado