That senario is eerily similiar to a problem that plagued the older Freestars.I mean the Windstar.
It would be sad if the O2 sensors were dying at 66K. Or that a computer or EEPROM had problems.
Seriously, If it is intermittent, I would check for vacuum leakage at the intake gaskets, EGR passages for carbon buildup causing blockage, Possibly an intermittent voltage drop at a harness/component connector, but without checking TSB's or Recall info, I would hope those things, or intake gasket/valve cover design and related problems are not found to be the cause.
Maybe you will find that it was just a one time fluke or "glitch" and will not re-occur.
I will research this symptom and reply with any additional information I find of value.
Monday, March 17th, 2008 AT 2:13 PM