The freezer was clean out of chuck, so I did a 6-pounder today, using Dizzy Pig Cow Lick rub. (The next one will be WRB, Larry.
A strange thing happened during the cook. The cooker temp was holding at 267°, a tad warmer than I intended. The meat was at 160°, and I figured it was going to plateau for a while. The next time I looked, about 20 min later, the cooker temp had jumped to 322°! Meat was at 165°, my foil target, so I double-foiled, and after all that opening and closing, the cooker temp dropped back below 300°. I had the vents all
shut down by this point. Cooker temp stayed in the 290's from then on. When the meat reached 198° I took it out, wrapped it, and put it in the cooler. The roast was done in almost exactly 1 hr/lb!
The meat pulled easily and has good taste and texture, so no complaints. But what the heck might have caused the cooker temp to spike like that, 55° in a few minutes? (I had started with a full ring of Kingsford using the Minion Method, and it came up to temp normally, except as I said, around the 4-hr mark it was running a little hotter than what I had in mind.)