1999 Corvette: Service Bulletin: Hesitation, Sag, Stumble and/or Backfire on Acceleration (Reprogram PCM)

Subject: Hesitation, Sag, Stumble and/or Backfire on Acceleration
Source: Chevrolet Service Bulletin
Number: 99-06-04-030
Models: 1999 Chevrolet Corvette with 5.7 L Engine (VIN G -- RPO LS1)

Condition:

Some customers may comment on a hesitation, sag, stumble and/or backfire on acceleration during cool summer days/evenings with ambient temperature below 10°C (50°F).

Cause:

Condition may be due to lean calibration with Low Reed Vapor Pressure Fuels (summer grade premium fuel) at lower ambient temperatures, below 10°C (50°F).

Correction:

Reprogram the PCM with a new service calibration.

Parts Information

Previous Calibration P/N	New Calibration P/N
16263856	16263683
16263857	16263701
16263858	16263709
16263859	16263710

The calibrations listed are electronic calibrations and are NOT available from GMSPO. Calibrations will be available from Techline on the 1999 Disc 10 CD ROM or the TIS 2000 Disc 12 CD ROM.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these 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 your GM dealer for information on whether your vehicle may benefit from the information.

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