Had the same thing happen to me in my 2004 Cummins, while pulling a 48' enclosed trailer on my way to the track in Indy! Was on the interstate on the west side of Indy. Fortunately it was at 1 am in the morning and not a lot of traffic.
Found out later, it was the throttle position sensor switch, had to replace, it was like $600.00. Was told if it happens again, turn the ignition switch off and on rapidly about 6 times and it would temporarily fix it.
Believe me when your truck and race trailer just goes dead on an interstate, it is a sick feeling!!! HEMI JOE