I just recently bought my Acadia through a lease buyout. It's an SLT-1 with 11k miles. I've noticed that once the car is warm it gets a low growl that increases with RPM. I can feel it through the accelerator pedal as well. It is engine-related as I have put the car in Park and slowly revved it and heard the growl increase with RPM. I know the previous owner and he said the dealer told him it was normal, but is a disconcerting sound nevertheless. Has anyone else experienced this as well? I'm getting ready to take it in for a freebie oil change at the dealer and I'll bring it up again with them at that time.