One problem related to steering idler arm has been reported for the 2010 Ford Fusion. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2010 Ford Fusion based on all problems reported for the 2010 Fusion.
2010 Ford Fusion idler pulley bolt sheered off along with piece of engine block and pulley resulting in a near accident as drive belt, and power steering failed and vehicle would not go past 20 miles per hour (on highway). My wife (5 months pregnant) was driving at the posted speed of 70 mph when the pulley and bolt sheered off. Her car was nearly struck from behind by several vehicles as well as not being able to steer the car herself. Looking at Ford Fusion blogs, this appears to be a common problem that Ford has not fixed in their earlier models. This design and/or stress fault causes safety concerns as well as costly repairs since piece of the engine block can sheer off with the idler pulley bolt.