CHUGGLE TIP IN HESITATION REVISED EGR AND PROM

This bulletin replaces bulletin 82-T-124 dated November, 1982 due to a incorrect published EGR part number. Bulletin 82-T-124 should be destroyed and replaced with this reissue.

PROM, P/N 1225707, and EGR valve, P/N 17079787, with revised calibrations, are available for any combination of the conditions listed below which might occur on 1982 California Impala and Caprice models with 3.8L V6 engines. It must first be determined that affected vehicle systems are within speci- fications and functioning normally before installing these parts.

A. Chuggle at 40-45 mph B. Tip-in hesitation

Vehicle should be road tested to verify the owner described conditions. Unless all other areas are correct, the PROM and EGR valve will not be effective. Use the attached check lists for additional assistance, as necessary.

A. Condition: Chuggle - also referred to as surge, is most noticeable at 40-45 mph, and should not be confused with "freeway hop", a common condition in many areas. Converter clutch engage speed is increased to 50 mph from 41 mph.

B. Condition: Tip-in Hesitation - may be experienced during either hot or cold operation, while going through a light or moderate acceleration period, from a stationary vehicle position.

If any one or combination of conditions exist, install both parts, PROM and EGR valve. These parts were used in production for 1982 model vehicles.

PARTS INFORMATION

Obtain the following two (2) parts from your GM Parts Division Warehouse:

Original Equipment PROM ID

Prom, P/N 1225707 16030034 BOH EGR valve, P/N 17079787

CHUGGLE CHECK LIST

Park-neutral back up light switch adjustment Base ignition timing and total advance Spark plugs and plug wires HEI operation at problem speeds - includes checking for correct distributor wave washer Speedometer needle for fluctuation (sticking or kinked cable and/or speedo head will cause vehicle speed sensor (VSS) to engage - disengage TCC)

Evaporative Emission Control System (EECS) - purge solenoid operation - hoses and correct hose connections - canister vent valve operation

HESITATION CHECK LIST

EGR valve system operation Accelerator pump system operation - pump shot Vacuum hoses, fittings and connections Ignition timing Carburetor float level 9/32 +/- 1/32 C-3 wiring proximity to high voltage wiring EFE system operation T.A.C. system operation Overheating - cooling system problem Incorrect spark plugs Bad fuel EGR override relay circuit MAP/BARO sensor operation

WARRANTY INFORMATION

Labor Operation Number: T0112

Labor Time 0.6 hours

Replace PROM and EGR valve system performance check not necessary.

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.