I had the same issue in my 2016 2.4 liter. In my case it was like the engine was lugging [Eco mode selected]. Here is the complex way I solved it: I let the fuel get to where about 1/4 tank remained. I filled the tank with premium fuel [91 octane in CA] and voila, problem solved. At low RPM the computer is programmed to take advantage of torque. Unfortunately that caused the exhaust noise/rumbling/vibration. Premium fuel combusts more slowly and over a longer time as opposed to regular 87 octane that combusts quickly. That sharpness is what causes the vibration/rumble. I tried various combinations of low, mid and premium but only straight premium solved the largely aesthetic problem. Unfortunately using premium fuel isn't offset by higher mpg. With a light foot regardless of grade of fuel I regularly get 32-33 mpg highway on an 800 mile driving cycle from San Diego CA to Mammoth Lakes CA and back. I don't drive over 70 mph unless I need to pass. I am impressed such a large, heavy vehicle can get 32-33 mpg. So I splurge on premium fuel now. Vehicle has 3,600 miles on it. Hope this helps.