C 2500 Truck 2WD V8-5.7L VIN R (1997)
Malfunction Indicator Lamp: Customer Interest
PROM - MIL ON, Poor Driveability Condition
File In Section: 6E - Engine Fuel & Emission
Bulletin No.: 76-65-04
Date: March, 1997
Subject:
Malfunction Indicator Light (MIL) On, Poor Driveability Conditions
(Perform Flash Calibration)
Models:
1996-97 Chevrolet and GMC Light Duty Trucks
1996-97 Chevrolet Tiltmaster and GMC Forward W4 Models
1996-97 Oldsmobile Bravada
with 4.3L, 5.0L, 5.7L Engines (VINs X, W, M, R - RPOs LF6, L35, L3O, L31)
Condition
An owner of the above mentioned vehicles may report that the Malfunction Indicator Light (MIL) is on and/or the vehicle has one or more of the
following driveability conditions.
1.
5.7L (L31) only: Surge or chuggle at speeds of 42 to 65 MPH while at steady speed or under light to moderate acceleration with the TCC applied.
2.
MIL on with DTC P0172 or P0175 stored but no reported driveability symptoms.
3.
MIL on with TDC P1406 stored and rough engine or poor driveability symptoms.
4.
When operating at altitudes above 5,000 feet, an audible spark knock noise is heard.
5.
Hesitation and/or misfire during light cruise conditions due to ignition cross-fire with no DTC stored. This will only occur on V-6 engines with
cam retard offset in excess of 26° and V-8's with cam retard offset in excess of 15°.
6.
The MIL may be on and a DTC stored for an engine misfire but no misfire occurred.
7.
Engine exhibits an idle speed surge or roll.
1996 Models Only
8.
MIL on with DTC P0102 stored but no reported driveability symptoms.
9.
5.0L (L30) & 5.7L (L31) only: Difficult starting in extreme cold (below 0° F) conditions.
10.
5.7L (L31) only: Poorer than expected fuel economy when heavily loaded.
1997 Models Only
11.
MIL on with DTC P0121 stored but no reported driveability symptoms.
12.
C/K & S/T Models with either V-6 engine and manual transmission: An engine flare between shifts may be noted when the engine is cold.
13.
Either V-6 engine and manual transmission: An engine flare between shifts may be noted when the engine is cold.
14.
C/K, S/T and M/L Models equipped with L35 V-6 engine, an improvement to the vapor canister purge diagnostics is incorporated into the new
calibrations so that the Tech II can turn on canister purge at idle speed.
Correction
