Start by changing out the fuel filter, you may have gotten bad diesel. I'm probably going to bank on your PMD being shot, its the driver that controls the injector pump and is a VERY common failure on the H1. I wrote an article on it and how to change it out/mount it remotely a few years back.
http://flashoffroad.com/Diesel/injectionpump/fsd.htm
http://flashoffroad.com/Diesel/injec...FSDInstall.htm
Take the truck in and have the codes pulled. If there are not codes and the stalling persists you can bet it the PMD. Very rarely will a PMD failure give any codes. If it is in fact bad make sure to mount it remotely, this will reduce the chances of it failing down the road. And if it does replacing it is a 15 minute job, putting it back on the injector pump is BIG $$$ and only ensures that you will have to replace it again, mounting it on the pump was a design flaw.