COLD DRIVEABILITY EFE-POOR LOW TEMP. PERFORMANCE

VEHICLES AFFECTED: 1984 Light Duty C/K/G/P Models

THIS CANCELS AND REPLACES PRODUCT SERVICE BULLETIN 6-232, SEPTEMBER 15, 1984 WHICH SHUULD BE DESTROYED. THIS COPY IDENTIFIES APPLICABLE VEHICLE APPLICATIONS. VIN EMISSION ENGINE MODEL ENGINE SYSTEM CODE ----- ------ ------ ----

Pickup, Van, Suburban, and Blazer 5.0L V8 Federal H

Pickup, Van, Suburban, Step Van, and Chassis Cab 5.7L V8 California M

Pickup, Suburban, and Motor Home 7.4L V8 California W

Some 1984 trucks, as listed above, may exhibit poor driveability and performance when cold. When diagnosing cold driveability and performance comments, refer to the Shop Manual Driveability and Emissions Diagnosis Section. If the condition cannot be resolved by normal diagnostic procedures, check the EFE (Early Fuel Evaporation) valve for proper operation (Chart C-9C).

After startng the cold engine, observe the EFE valve. If the EFE valve does not close, follow the diagnostic procedure shown on hart C-9C. If the condition is not corrected, the following revision should be performed.

Remove the EFE check valve from the vacuum supply line as shown.

2. Reconnect the vacuum supply line by inserting a straight hose connector, P/N 560625.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.