I've had my BGE (large) a few months and I'm beginning to get a better feel for temperature control with the unit at lower temperatures. However, I'm having a lot of trouble with temperatures above, say, 400. I've tried cleaning out all of the ash with a shop-vac, starting with the maximum amount of lump, letting it burn for an hour or so with the vents wide open before I try to control the temperature, and most recently, I set up a little computer fan to blow into the lower vent to keep the air circulating. I think that the problem is even worse if I'm using the plate-setter. I'm using BGE lump. Anything else that I can try besides moving to a lower elevation?