You can check the lift pump yourself very easily. With the engine idling, open the air bleeder on the fuel filter. Fuel should shoot out of it several inches with no air coming out of it first.
Next, you should have a small brass T handled valve by the thermostat on the coolant crossover at the front of the engine. Again, with the engine idling you should be able to open this and drain out water and sediment from the filter housing without the engine stalling. If it stalls, the lift pump is probably not running.
You can also put a pressure gauge on the fitting at the valve too; the pressure from the lift pump should not be less than 5psi, and not over 9psi.
You're going to have a heck of a time finding anyone who'll work on a 6.5L and is competent; they're very few shops that are knowledgeable about them, and the dealerships often won't touch them either, and know almost as little and most shops.