I am a new owner of a 2013 F150 Ecoboost SCrew FX4. I have 2500 miles on it so far. My previous ride was a 2001 F250 with a 7.3L. I thought I gave up the engine knocking, however, it sounds like it followed me to the Ecoboost. Does anyone else hear that knock while at idle? Is this normal? If so, what is it caused by?