praz

I have 2015 Edition 507 with 22k miles and have this odd issue with the accelerator. When low to medium acceleration, it is smooth and no issue. When I punch it there is this grinding noise and physical feedback in pedal. Its not constant but in short bursts while pedal is down. When I back off the pedal to maintain speed or slowly accelerate the issue no longer presents. I have taken it to the dealership and had the accelerator mechanism replaced and its still having the issue. Anyone else faced this? I did a few searches on the forum and couldn't find anything.