DELAYED AND HARSH UPSHIFTS THROTTLE BODY ASSEMBLY
VEHICLES AFFECTED: 1987 'A,J AND L' CARS WITH 2.8L MPFI V6 ENGINES (LB6) AND AUTOMATIC TRANSAXLES
THIS BULLETIN SUPERSEDES BULLETIN 87-628-102, 87-7125-101, 87-7440-103.
Some early built 1987 'A, J and L ' cars with 2.8L V6 engines (VIN Code W) and THM 125C (MD9) or 440-T4 (ME9) automatic transaxles may exhibit delayed and or harsh upshifts.
After the condition has been verified, inspect the Throttle Valve (TV) cable for proper operation and adjustment. (Follow the T.V. cable adjustment procedures contained in the "Automatic Transaxle Section" of the appropriate Service Information Manual). If the T.V. system is operating properly and the condition still exists, it may be caused by insufficient travel of the throttle lever on the throttle body assembly.
Inspect the throttle lever for an identification hole in the location shown in the Illustration. If the lever has a hole, continue following the diagnosis covered in Automatic Transaxle section of the Service Manual If the lever does not have a hole in it at the location shown, install a new throttle body with a revised throttle lever. Throttle body service kits are as follows:
All "A" cars except Pontiac STE Model 17111886
Pontiac STE Model 17111884
"J and L" cars 17111882
NOTICE: THE SERVICE THROTTLE BODY KIT INCLUDES ONLY THE CORE THROTTLE BODY. IT DOES NOT INCLUDE THE FOLLOWING PARTS, WHICH ARE AVAILABLE SEPARATELY:
- COOLANT COVER AND ATTACHING SCREWS - IDLE AIR CONTROL VALVE, HOUSING AND ATTACHING SCREWS - THROTTLE POSITION SENSOR AND ATTACHING SCREWS
THESE ITEMS CAN BE TRANSFERRED FROM THE ORIGINAL THROTTLE BODY ASSEMBLY.
Follow the throttle body removal and installation procedures covered in the "Driveability and Emissions-Port Fuel Injection Section" of the Service Manual. After installing the replacement throttle body, preset the throttle stop screw as follows:
- Back throttle stop screw out until it breaks contact with the throttle lever. Turn screw in to lightly contact lever, then 1 3/4 additional turns. Final minimum idle speed adjustment should be performed following the prodcedure covered in the Service Manual.
- Adjust minimum idle speed to 550 RPM plus or minus 50 RPM.
- Adjust TPS to 0.55 volts plus or minus 0.1 volts (0.45 to to 0.65 volts)
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.
