Engine - Surges

88chevy15

GMC NUMBER: 88-T-157

GROUP: 6E-Engine Emission

DATE: August, 1988

CORPORATE
NUMBER: 836512R

SUBJECT: ENGINE SURGE

MODELS: 1987-88C/K, R/V TRUCK WITH 7.4L (VIN CODE N) ENGINE


THIS BULLETIN CANCELS AND REPLACES BULLETIN 88-T-95, ALL COPIES OF WHICH SHOULD BE DESTROYED. THIS REVISION IS TO UPDATE PROM P/N FOR MANUAL TRANSMISSION AND ADD AN AUTOMATIC TRANSMISSION PROM.




Some 1987-88 C/K and R/V trucks with 7.4L engines may experience customer comments of engine surge. If the condition described cannot be repaired using normal service procedures, a revised calibration PROM should be installed (see chart). Parts are currently available from GMSPO.

After the PROM change, if surge is still present at highway speeds, refer to Bulletin 88-T-141 dated July, 1988, for MAP sensor repositioning.

Use Labor Operation: T7655
Labor Time: .6 Hr.