GMC 1999 Sierra 1500 Pickup Owner's Manual page 288

Service & Appearance Care
Running Out of Fuel (Diesel Engines)
If the engine stalls and you think that you've run out of fuel, do this:
6.5L Engine
c
F -
P
6.2L
Engine
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First, open the fuel filter air bleed valve or remove the screw. If there is air,
then you are probably out of fuel.
To restart your engine:
1. If you're parked on a level surface, add at least two gallons of fuel.
However, if you're parked on a slope, you may need to add up to five
gallons of fuel.
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