Around 102, 000 miles, during a snow storm, i was driving my 2005 ford five hundred awd limited on a main road. as i was driving, the car seemed to "lurch". i reacted by removing my foot from the gas, in fear the car was sliding on ice, and the wrench illuminated on my dash, as it displayed "failsafe engine mode". the car continued to drive, and the engine was still running. however, it was not handling very smoothly. i pulled over and turned the vehicle off. i waited ten seconds and started the car. everything was fine. i began to drive on the road again, and the situation repeated. the car seemed to shift very hard, and the wrench illuminated and "failsafe engine mode" was displayed. the check engine light also illuminated. i pulled over and turned the car off again. once i turned it back on, the check engine light was still on. two days later, i disconnected the battery and when the car was reconnected, the check engine light had turned off. atleast one month passed with no problems or re-occurrences. however, this morning, there was another snow storm. while i was driving, the car lurched again, the "failsafe engine mode" displayed, and the check engine light is on again. both occurrences have been followed by the inability of my car to drive well in the snow. both times my car has fishtailed horribly, and been difficult to maintain. this problem did not occur until this winter, and i have had it since august of 2008. *tr