I am not a Diesel Tech and I am in no way diagnosing a problem. I have been reading posts on the surging/stalling issues with responses being egr/ebp/ wiring harness etc..
I had the same problem (before engine replacement) and it only appeared after my first oil change at the dealer. The problem occurred after a minimum of 30 minutes of highway speeds. Of course the diesel tech could not duplicate the problem and replaced the harness.
I read a post stating too much oil could also be the cause of this problem. I spoke to a Diesel Tech this morning and he explained too much oil could cause a surging or stalling problem however it would take more than one or 2 quarts over full to create a problem.
It would be interesting to see how many of you with this problem have checked your oil level carefully. I remembered that my oil level was above the plastic minder on the dipstick after the first oil change. If you are having the Surging problem check your oil level and post your results. If it is high ask your Tech.