I have a 2001 3500 cab & chassis w/8.1 and alli(70K on the mileage). I was driving home from a job and the truck just died. I was going up an on-ramp with a 90deg. rt turn on to the fwy at about 15mph. Truck would not start all. Tried and tried. Had it towed to the dealer. The tech could not duplicate problem, no codes thrown and it started right up. (had just over a 1/4 tank of gas in the two tanks).They had it for 2-days and tried everything and no duplicate.
I now have had the truck back for a week and it has died at least 10 times. Change the fuel filter and filled up with a full tank. Died 3-times. Every time since it starts right up. I have noticed that it mostly dies right after I have started it up and have driven it 2-3miles. It has only done it twice while the truck was warmed up. Any body have any ideas? Dealer say can't do anything if it doesn't a code. Help. Sorry about the long thread, but I thought I would give all the info.

Hello, If I was you I'd look long and hard at replacing the crank sensor with the "new" updated variety......the 2001 were noted for having intermittent stall failures, and then they will restart...no codes set....:)
Sir-Col

Sir-col, are you talking a crank sensor or cam sensor? I had the cam sensor replaced 2-times under warranty. Thank you for your help.

It sounds exactly like the problem I had with the Crank Position Sensor.

Hello again, The crank position sensor, .....on the 8.1 it is located at the rear of the engine simular to where you would look for a distributor (in the old days) and it functions internally .....unplug, unscrew, and R/R, plus relearn etc.
Sir-Col

crank sensor... my 02 did same. It's located behind the left cyl head, in bellhousing area, not much room in there but it'll wiggle out. BTW mine didn't set any codes either.

The truck died today and finally wouldn't start up, but the (SES) finally went off. Took it to a local shop and sure enough the crank sensor was the problem. Thats to those who responded with the answers. Great forum.:ro) Greg