STALL/SURGE AFTER COLD START DIAGNOSIS P/N FOR NEW PROM

1986 6000 AND 6000 LE MODELS WITH 2.8L V6 (VIN CODE W) MPFI ENGINE AND 4 SPEED AUTOMATIC TRANSMISSION

Some 1986 6000 and 6000 LE models with 2.8L V6 MPFI engines and 4 speed automatic transmissions may experience unstable or rough idle after cold start at ambient temperatures between 50 to 70 F. To correct this condition inspect for the following and correct as necessary:

1. Loose or leaking air duct between mass airflow (MAF) sensor and throttle body.

2. Low minimum air rate and/or TPS setting.

3. Leaks in the EGR transfer tube and/or connections.

If the condition persists, replace the PROM with one of the following service PROMs:

MODELS SERVICE PROM 6000/6000 LE EMMISIONS HTR/AC PART NUMBER CPE,SED Federal HTR 1228071 CPE,SED Federal AC 1228070 STA. WAG. Federal HTR 1228101 STA. WAG. Federal AC 1228085 CPE,SED California HTR 1228078 CPE,SED California AC 1228072 STA. WAG. California HTR 1228103 STA. WAG. California AC 1228102

NOTICE: The above PROMs are for 6000 models, (except STE) 2.8L port fuel injected engines with 4 speed automatic transmissions.

Use applicable labor time and operation numbers.

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.