For 1990-2009 cars

# HESITATION ON ACCELERATION DURING COLD DRIVE-AWAY

#### VEHICLES AFFECTED: 1985 'F' Cars With LB9 5.0L TPI Engine (VIN Code F

Customer comments may be received on 1985 'F' cars with 5.0L TPI engines regarding a hesitation when accelerating when the vehicle is cold.

This condition can be corrected by:

1. Installing a revised service PROM.

Application PROM P/N ----------- -------- Chevrolet With A/C 1227739 Chevrolet W/O A/C 1227740

2. Set minimum idle speed to 500 RPM as described in your 1985 Shop Manual on page 6E3-101.

#### NOTICE: These service PROMs contain additional calibration changes designed to enhance veliicle driveability. Engine idle speed will be raised to 650 RPM and TCC engagement speed will be raised to 65 KPH (41 MPH).

Use applicable labour time and operation numbers.

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.