The 1991 Pontiac Firebird, Formula, GTA, and Trans Am rear towing procedure has changed.
The 1991 General Motors Passenger Car Towing Manual (T-62) does not state the following change:
The 1991 Pontiac Firebird, Formula, GTA and Trans Am MUST NOT be towed from the rear with sling-type towing equipment. Use either wheel-lift or car carrier equipment to transport this vehicle.
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.