So I have taken two trips to PA from NY and logged about 600 miles over the last two weekends. I did experiment with the Eco light to see when MDS kicks in and out. I definitely noticed a more pronounced and frequent knock when lightly accelerating in Eco mode (4 cylinder) and it goes into 8 cylinder mode. When I engaged the shift points on the steering wheel to -8, thereby bypassing Eco mode, it was quieter, knock wise when accelerating lightly. But, when accelerating harder from let's say 50 MPH to 65 MPH, I could here some knocking for a second or two. This required a harder press of the accelerator, but I could hear it. I tried this many times, on level as well as hilly roads. So I thought I had it figured out with the Eco mode cycling on an off but now I am convinced that is not entirely the issue. Can the dealer tell by hooking it up to a scan tool if the lifter(s) is/are bad? I have a feeling this is going to be a tough dealer fight since it took me quite a bit of road time to finally hear the differences under different driving modes.