Took the Mach to the dealer Thursday for knocking sound in the left (drivers)side of the engine. It's an '04 with a little over 1300 miles on it and the noise started a couple of hundred miles ago. The service dept. mgr. said there was a technical service bulletin for '03 Machs concerning this problem, but not for the '04s. He called back Friday and told me that they had been on the phone with Ford and were told to pull the left head for further inspection. He said they would most likely replace the head, and if there was any sign of metal in the oil, they would replace the engine. Anybody out there heard of this?