I have a 2002 Ford F350 4X4 7.3L Power Stroke Diesel, with approx 75000 miles. When I slow down to come to a stop sign or red light, or just for slow traffic, the engine will shut off. It will not spit or sputter, it just quits. I have taken it to Ford Service and they cannot find any codes or duplicate the problem. This has occurred 6-8 times in the past 3 months. What could be the problem?