Did you figure it out? My 06 2500 has some sort of fast warmup function that raises the idle and closes the vanes in the turbo to speed warmup. I don't have it enabled, so I don't know if it's exactly what you're seeing, but it sure sounds the same. It cuts off if you touch the throttle. Oh, and we don't have exhaust brakes... Wonder if EFI live could make one for me?
The Constitution needs to be re-read, not re-written!
If you can't handle Dr. Seuss, how will you handle real life?
Current oil burners: MB GLK250 BlueTEC, John Deere X758
New ride: MB GLS450 - most stately
Gone but not forgotten: '87 F350 7.3, '93 C2500 6.5, '95 K2500 6.5, '06 K2500HD 6.6, '90 MB 350SDL, Kubota 7510