You may notice that your meat steadily comes up in temperature, all the way up to 150° or so and you think you're home free and finishing way faster than you thought. But then, the dial stops moving. This is called "the stall" and is completely normal. It can last anywhere between 2-6 hours. Stay patient and you will get over that hump eventually. This is where all of those tough connective tissues start to break down and the bark starts to develop.