PROM - Backfire/Hesitation, Low Power/Surge In High Gear

Group Ref.: Engine Fuel & Emission
Bulletin No.: 376516
Date: January, 1994

SUBJECT:
BACKFIRE/HESITATION (SAG) ON LAUNCH, LOW POWER (SURGE) IN HIGH GEAR

MODELS:
1993 CHEVROLET AND GMC C/K TRUCKS WITH 4.3L ENGINE (VIN Z - RPO LB4) AND MANUAL TRANSMISSION

CONDITION:
Some owners may comment on one or more of the following conditions.

1. Backfire on initial acceleration from a standing start and/or backfire when accelerating at low speeds in high gear.

2. Hesitation or sag on initial acceleration from a standing start.

3. Low power or perceived engine surge when accelerating at part throttle in high gear and/or low power at part throttle when climbing hills in high gear.

CAUSE:
System/component variability.

CORRECTION:





Install the correct service PROM from the table.

PROM Information: All PROMs are NA1 (less than 8500 GVW)

Parts are currently available from GMSPO.

LABOR TIME:

Labor Operation: T0500 - PROM, PCM-Replace

Labor Time: 0.6 hour