Truck has been sitting for a couple of months but I started it recently & it will run for a couple of minutes then shuts off. It seems to be starving for gas. What could be the problem?

Bad or old gas, moisture in the tank. Add a bottle of moisture reducing product to the tank. There are several brands on the market. I.e. Heat. Then add some new fuel. If you intend I'm not using the vehicle regularly do not leave much fuel in the tank.