COLD DRIVEABILITY EFE-POOR LOW TEMP. PERFORMANCE

Model and Year: 1984 10-30 "C/K/G/P" MODELS

TO: ALL CHEVROLET DEALERS

This cancels and replaces 84-178 dated August, 1984 which should 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 drive- away 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 by resolved by normal diagnostic pro- cedures, check the EFE (Early Fuel Evaporation) valve for proper operation (Chart C-9C).

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

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.