I'd start with checking the oil level and finding out where the leak is coming from.

When the truck stalls after 3 - 10 min., can you describe how it stalls? I would think a fuel restriction would show up cold or hot, but you said the truck runs fine when the engine is at operating temp.

Make sure the oil is of the proper rating, then if possible, monitor live data on a scanner to check for a biased sensor. The EOT sensor comes to mind, but I'd check as many as you can.