ENG. SURGE AT PART THROTTLE REPL. MEMCAL AND EGR VALVE

SUBJECT: ENGINE SURGE AT PART THROTTLE OR WHILE CLIMBING GRADE (REPLACE MEMCAL AND EGR VALVE)

VEHICLES AFFECTED: 1991-92 "S" TRUCK WITH 2.5L ENGINE (VIN CODE A) AND MANUAL TRANSMISSION

CONDITION:

---------- Some owners of 1991-92 S-trucks with the 2.5L L38 engine (Vin Code A), Federal emissions, manual transmission and 3.73 rear axle may comment of an engine surge occurring in the RPM range of 2000-2500 RPM, at a steady throttle or while climbing a slight grade.

CAUSE:

------ Unstable combustion due to EGR (Exhaust Gas Recirculation) flow.

CORRECTION:

----------- Install a new memcal and EGR valve.

Memcal P/N: 16183223 Scanner ID: 3241 Broadcast Code: BCNX

EGR Valve P/N: 17112238

For vehicles repaired under warranty use:

Labour Operation: Memcal, replace Labour Time: 0.5 Hours.

Labour Operation: J6270 EGR Valve, replace Labour Time: 0.6 Hours.

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.