6.0 Excursion Stalling - Need advice

2005 6.0 Diesel Excursion starts to stall, then gas pedal goes to the floor and vehicle won't move, only idle and then stalls completely and won't start. After a couple hours the vehicle runs fine and then it stalls out again with no acceleration. ERG just replaced. Anyone else heard of this problem, and no what the fix could be???? Been paying for a rental car for 7 days, while service center is trying to figure it out........