Hello all, new to the thread. I just purchased a used 2020 ST 2 weeks ago and have started noticing a fairly harsh rumble when I accelerate (normally) from a stop, or even a rolling start. Seems to be around a certain RPM, maybe 1300-1500 if i had to guess. The rumble also occurs on deceleration, at the same RPM. I read a lot about the flex pipes, but im not sure if that is the cause. The entire pipe on the driver side is rumbling upon startup, and I can tell by the sound that it is the same rattle that I am experiencing while driving. What could the diagnosis be?