Have a whole 12lb brisket cook in progress. In about hour 4, temps have been hard to control, between 250-300 at the grid measured by my BBQ Guru probe. I actually have the Guru fan out and the bottom vent closed all the way and it's still holding at 300 and not dropping but that's another issue. I have wrapped it in foil for maybe an hour or so and my temps are already reading 200+ in the flat and point.
It can't be done that fast, its impossible. What should I do?