truck drops idle and cuts off

[mdkallam130]

just out of curiosity..what would cause a 2002 7.3 to want to go from idling at like 800-900 to drop to like 500-600 when putting the truck in reverse and truck cuts off some times...this happens mostly when the truck is cold but has happened after my forty mile trip to work thru light traffic.. just curious what the techs might think is going on.

i have just recently replaced the cps(like about a month ago) just wandering what this would be. truck has 173000 miles on it