A condition of stalling or rough running after quickly returning to idle from high rpms may be caused by the lash adjusters holding the valves opened until oil pressure drops.
When replacing the cylinder head, this may be caused by forgetting to transfer the valve spring seats to the new head which greatly reduces seat spring pressure and will allow the valve to stay open.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.