HES./SAG COLD/ SURGE WARM INSTALL REVISED ECM AND PROM

VEHICLES AFFECTED: 1985 'R' CAR

Some of the subject vehicles may experience engine driveability complaints of hesitation or sag when operating under cold engine conditions and surge at warm engine operating temperatures.

In order to effect an improvement, a revised ECM was introduced during 1985 production. Complaint vehicles can be corrected using this ECM per the following information:

Automatic Transmission - VIN prior to F8421857

Use controller - ECK P/N 1227077, with calibrator, 1227729

VIN F8421857 and later: Replace existing PROM with calibrator, 1227729.

Manual Transmission - VIN prior to F8422417

Use controller - ECM P/N 1227077, with calibrator 16051549

To further improve engine driveability on automatic transmission cars, the following part sho'uld also be installed: pump arm kit-accelerator, P/N 94426520.

Use existing labour time.

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.