My vehicle has been in the shop for nearly 3 weeks. The engine began knocking at idle after 2nd oil change at 10k miles. Vehicle is stock - non abused. The service manager thought it may be the lifters - they called ford rep and ended up replacing lifters - no fix... Then ford asked to do the TSB for ac tension ears... No fix. Ford then wanted the head replaced - which is where I am now. When I dropped the car off the dealer wouldn't't provide a loaner so I paid for a rental on my own dime. I was going to take it from them to a different dealer, but they stated the knocking was so bad they would not allow it without voiding warrantee. I got ford corporate involved this wk and they at least put me in a rental. Meanwhile, my 2012 GT is slowly being torn into and worked on in whatever manner of guessing Ford can drum up.