this sensor measures egr flow.it could cause a lean misfire.they are a common failure items on fords.I would check connector on dpfe sensor since intermittent.clear light and see if comes back on.do you have any testing tools?multimeter?scan tool?hand vacuum pump?not too hard to test this sensor.a scan tool with data stream is nice but could use a multimeter.the vacuum pump you monitor dpfe snesor signal voltage while applying vacuum to sensor.ford redesigned this sensor several times.chances are it is the sensor but could be the circuit also.let me know.