6.5 diesel Stalling

I've got a 94 1500 silverado with a 6.5 liter diesel running about 220,000 miles. After 5 mins or so of driving it will stall out. After restart it'll run for 10-15 seconds and then die. If you let it sit for 20 mins you can get another 5 mins. of driving with it. I thought it was water in my fuel so i added fuel dry, empty'd fuel out of both valves on the motor, shown below, new fuel filter, plus i let it idle for 4 hours with the fuel dry. After that it was good for a day and now its acting up again. My manual said there was a valve on the bottom of the blue filter element to drain water but when i stuck my hand underneath it was just smoot on the bottom. Any help would be awsome. thanks guys.
http://img.photobucket.com/albums/v681/MasterJ220/DSC00140.jpg
http://img.photobucket.com/albums/v681/MasterJ220/DSC00138.jpg

It sounds like fuel pressure. Check the fuel pressure to the injection pump. Should be 4# or more.