ENGINE DRIVEABILITY (VFV OPT.) NEW REPLACEMENT PROM RELEASED)

Subject: ENGINE DRIVEABILITY

Model and Year: 1991 LUMINA WITH 3.1 L AND VARIABLE FUEL VEHICLE (VFV, N14) OPTION -----------------------------------------------------------------------------

Condition:

---------- Owners of some 1991 Luminas with 3.1 L Variable Fuel Vehicle (VFV, N14) option may exhibit tip-in hesitations or tip-in stalling. This condition may be most noticeable after cold start-up when running on low alcohol blends.

Cause: This condition is due to lean air/fuel ratios on tip-ins. ------

Correction:

----------- To correct this condition install a new service calibration PROM, which revises tip-in fueling. Reference the chart below for the proper PROM application.

Series Engine Trans. Emissions Service PROM Broadcast P/N I.D. Code ------ ------ ------ --------- ------- ---- ---------

Methanol 3.1 Auto Calif/Fed 16173982 3991 BAHA Lumina

Parts are expected to be available on December 2, 1991. In case of limited inventory, parts will be placed on 400 Control to waive VIP surcharges. Only verifiable emergency VIP orders will be accepted. SPO will make every effort to obtain parts. However, the part will be shipped premium transportation at dealer's expense and all other order types will be placed on backorder until the 400 control is removed.

Note: The 1991 Methanol VFV Lumina Tech-1 cartridge is not compatible with this service PROM. A 1992 Methanol VFV Lumina Tech-1 cartridge will have to be used when trouble shooting vehicles equipped with this new service PROM.

Labor Operation: T0500

Labor Time: .7 Hour

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.