PROM - Engine Bump When Throttle Is Closed

Group Ref.: Engine Fuel & Emission
Bulletin No.: 376515
Date: December, 1993

SUBJECT:
ENGINE BUMP ON THROTTLE CLOSURE (INSTALL NEW FLASH PROM)

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

CONDITION:

Some owners may experience a bump while closing the throttle. This condition is most noticeable with a fully loaded vehicle or when the vehicle is on a grade.

CAUSE:

The engine calibration was too aggressive on leaning out the air fuel ratio on throttle closure.

CORRECTION:





Reflash the PCM with the new calibration. Regular vehicle production built after the VIN breakpoints (see illustration) already have this calibration from the vehicle assembly plant.





PARTS INFORMATION:

The new flash calibration will be available on the November STG CD. Part numbers

WARRANTY INFORMATION:

Labor Operation: T0500

Labor Time: 0.3 hours