For 1990-2009 cars

# TIP-IN HESITATION ON LIGHT THROTTLE ACCELERATION

#### SUBJECT: TIP-IN HESITATION ON LIGHT THROTTLE ACCELERATION (NEW FLASH PROM)

#### MODELS: 1994-95 BUICK SKYLARK 1994-95 CHEVROLET BERETTA, CORSICA 1994-95 OLDSMOBILE ACHIEVA 1994-95 PONTIAC GRAND AM WITH 3100 V6 ENGINE (VIN M--RPO L82)

#### CONDITION:

SOME OWNERS MAY EXPERIENCE A SLIGHT TIP-IN HESITATION ON LIGHT THROTTLE ACCELERATION DURING THE ENGINE'S WARM UP CYCLE.

#### CAUSE:

DUE TO ENGINE SYSTEM VARIATION, IT IS POSSIBLE TO SHIFT THE VEHICLE "RICH" IF THE VEHICLE HAS BEEN UPDATED WITH A FLASH PROM FROM SERVICE BULLETIN 57-65-24A. THE FLASH PROMS IN THAT BULLETIN WERE TO ADDRESS VEHICLES THAT WERE "LEAN" AND CAUSING STALLS. IT IS POSSIBLE TO SHIFT A VEHICLE "RICH" WITH THOSE CALIBRATIONS AND THUS INDUCE A RICH HESITATION. IF THAT HAS OCCURRED, NEW CALIBRATIONS ARE AVAILABLE TO "LEAN" THE ENRICHMENT ALGORITHM BELOW COOLANT TEMPERATURES OF 80 C (176 F).

#### CORRECTION:

IF SERVICE BULLETIN 57-65-24A HAS BEEN PERFORMED AND THE VEHICLE EXHIBITS A SLIGHT TIP-IN HESITATION DURING WARM UP AND NORMAL DIAGNOSTICS FAIL TO SHOW A CAUSE, THEN INSTALL A NEW FLASH PROM.

PARTS INFORMATION THE COMPLETE LISTING OF NEW FLASH PROMS WILL BE AVAILABLE FOR TECHLINE TOOLS STARTING WITH CD #14 RELEASE FROM THE GM SERVICE TECHNOLOGY GROUP (STG).

#### IMPORTANT: DO NOT ATTEMPT TO ORDER THE FLASH PROMS FROM GMSPO. THE FLASH PROMS ARE PROGRAMMED INTO THE VEHICLE'S POWERTRAIN CONTROL MODULE (PCM) VIA A TECHLINE TOOL DEVICE.

MODEL AXLE CALIBRATION YEAR CARLINE RATIO EMISSION NUMBER

94 N 2.97 NATIONWIDE 16247094 94 N 2.93* NATIONWIDE 16247084* 94 L 2.97 NATIONWIDE 16247064 94 L 2.93* NATIONWIDE 16247074* 95 L 2.93 NATIONWIDE 16247114 95 N 2.93 NATIONWIDE 16247104

*REQUIRES SERVICE BULLETIN 47-71-31 (REPLACEMENT OF FINAL DRIVE ASSEMBLY TO HAVE BEEN PERFORMED). THE STANDARD AXLE RATIO IS A 2.97.

WARRANTY INFORMATION FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR CODE: J6355 PROM REPROGRAMMING, ON CAR LABOR CODE: J6352 PROM REPROGRAMMING, OFF CAR LABOR TIME: USE PUBLISHED LABOR OPERATION TIME.

FIGURES: 0 ATTACHMENTS: 0

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.

COPYRIGHT 1996. GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.