Engine Controls - Increased Performance

88chevy24

GMC NUMBER: 88-T-113


GROUP: 6E - Engine Emissions

DATE: May, 1988

CORPORATE
NUMBER: 836515
SUBJECT: INCREASED PERFORMANCE

MODELS: 1988 S/T TRUCKS WITH 4.3L (VIN CODE Z) ENGINE AND CALIFORNIA EMISSIONS

Customer comments of lack of performance, poor tip-in response, or engine flatness may be received in connection with some early built S/T trucks with a 4.3L engine and California emissions. A new PROM was put into production that addresses these conditions. This new PROM is now available for trucks built before the following breakpoints:


GMC - 523895

The new PROM part number for the LB4 (4.3L) engine is listed below:

New New
Broadcast PROM
Emiss. New PROM Code I.D.
Type Trans. Axle Kit # PROM Label Scan Tool

Calif Auto (MD8) GU4 (3.08) 16124986 ANKB 5551
(NB2) GU6 (3.42)

For PROM replacement on vehicles under warranty use:
Labor Op: T7590 Labor Time: .8 Hrs.