why does my truck either stall or die while driving.

From your discription it seems the engine IS actually "running out of gas" and the poor performance issue is due to fuel starvation.. IF fuel 'level' is sufficient - It's possible the fuel in tank 1 is contaminated or the in tank fuel pump is failing .. Suggest having local repair shop have a look at it for you so a fuel pressure test can be performed... Got to be tested to determine the cause of this problem.