The following information supplements Service Bulletin 87-618-102, on rough idle or stalling after high rpm operation. The illustration in Figure 1 shows the proper orientation of the valve train mechanism. You will notice item No. 6 "Inlet Spring Washer" and its location. If left out, this prevents proper spring tension to be maintained and results in the conditions stated above. The exhaust valve uses a "Roto Cap" in the same location, see item No. 5.
Please note this in Section 6A of your chassis service manual.
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.