Originally Posted by
DBGrif91
You may have a hi pressure pump mounted on the frame. That could be what you're hearing with the second "whir." I don't know specifics of the system, but I think the hi pressure pump remains inert until the truck is running and accelerating, then kicks in to compensate for the extra needed pressure for acceleration. Cycling the key on and off may be causing it to kick in.
In a 95, each tank has an FDM. His truck won't have a third frame mounted pump.