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

SUBJECT: ENGINE SURGE AT PART THROTTLE OR WHILE CLIMBING GRADE

MODEL and YEAR: 1991-92 S TRUCK WITH 2.5L ENGINE

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

Part Availability:

Parts are currently available from GMSPO.

Warranty Information:

Labor Operation: T0500 Memcal Labor Time: .5 Hr.

Labor Operation: J6270 EGR Valve

Use applicable labor time guide for labor 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.