Fuel - Lack of Power/Hesitation on Acceleration

BULLETIN NO: 93-6E-112

SECTION: 6E Engine Emission

CORPORATE REFERENCE NO: 376509

NUMBER: 4

DATE: August, 1993

SUBJECT:
LACK OF POWER/HESITATION ON ACCELERATION (INSPECT AIR CLEANER/INSTALL NEW OUTLET DUCT)

MODELS:
1992-93 M/L Van W/4.3L Engine
CONDITION:

Some owners of 1992-93 model year M/L vans equipped with 4.3L (L35) V6 (VIN W) engines may report a lack of power or hesitation when accelerating under hot driving conditions. The engine will run fine otherwise and fuel economy will be normal. The engine will not miss, surge, or have a rough Idle. In general, no Diagnostic Trouble Codes (DTC) will be set.

CAUSE:

The outlet duct (duct between the air cleaner and the throttle body) may not have enough rigidity to withstand a rapid pressure drop under hot driving conditions and may temporarily distort.

CORRECTION:





Follow the diagnostic procedures for lack of power in the appropriate light duty truck fuel and emissions service manual. If no condition is found causing this symptom, inspect the outlet air duct. Determine if the latest design outlet air duct has been installed (see diagram of the original and latest outlet air duct). If the vehicle does not have the latest outlet air duct installed and was built before the following breakpoint:

GMC PB532742

Use the following procedure:

1. Remove original outlet duct.

2. Inspect air cleaner and remaining ducts for obstructions. Remove any obstructions found.

3. Install outlet duct P/N 25099916 (see figure).





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WARRANTY INFORMATION





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