If it will run if you hold the gas pedal down, the battery was likely disconnected or run dead. "Minimum throttle" must be relearned by the engine computer before it will know when it must be in charge of idle speed. To meet the conditions necessary for the relearn procedure to occur, drive at highway speed with the engine warmed up, then coast for at least seven seconds without touching the brake or gas pedals.
If this doesn't help, the air passage around the throttle blade could be plugged with carbon. This used to be a common problem with the 3.0L engine years ago when fuels went as clean as they are today.
Friday, February 26th, 2010 AT 8:04 AM