HOT HESITATION AT NORMAL OPERATING TEMPERATURES

1987 SAFARI, FIREBIRD AND GRAND PRIX MODELS WITH 5.OL LG4 ENGINE (ENGINE CODE H)

"This bulletin cansels and supersedes bulletin 87-6(Gasoline)-9,dated 11/86. All copies with this date should be destroyed."

Some early passenger cars equipped with 5.OL (LG4) engines and having VIN numbers prior to those listed below may experience one or both of the following driveability conditions:

a). Detonation prior to the engine fully warming up, or; b). Hesitation during a sharp tip-in maneuver with a fully warmed up engine (sometines called, "pump slug").

These conditions may be improved by installation of an accelerator pump check ball spring, P/N 17069583, and the appropriate service PROM from the table below:

Applicable VIN Numbers

Model Plant Prior to VIN Number ----- ----- ------------------- Grand Prix Ste. Therese All

Safari Fairfax 208979 (Federal Emissions) 209228 (California Emissions)

Firebird Van Nuys 223698 Norwood 232459

Service PROM Usage Table

Safari (LG4)

Station Wgn. 2.73 Fed. Emis. 16077198 Station Wgn. 3.08 Fed. Emis. 16077194 Station Wgn. 2.73 Calif. Emis. 16077563 Station Wgn. 3.08 Calif. Emis. 16077568

Grand Prix (LG4)

4 Spd. Auto. 2.41 Axle Fed. Emis. 16077306 4 Spd. Auto. 3.08 Axle Fed. Emis. 16077317 3 Spd. Auto. 2.41, 2.73 Axle Fed. Emis. 16077333 4 Spd. Auto. 2.41 Axle Calif. Emis. 16077321 4 Spd. Auto. 3.08 Axle Calif. Emis. 16077325 3 Spd. Auto. 2.41, ,2.73 Axle Calif. Emis. 16077329

Firebird (LG4)

4 Auto. 2.73 Axle Fed. Emis. P195/P215 16077174 Tires 4 Auto. 2.73 Axle Fed. Emis. P245 Tires 16077178 4 Auto. 2.73 Axle Calif. Emis. P195/P215 16077185 Tires 4 Auto. 2.73 Axle Calif. Emis. P245 Tires 16077189

Service Procedure:

1. Disconnect negative battery cable. 2. Install appropriate service PROM. 3. Remove air cleaner. 4. Remove air horn. Refer to Section 6CI of Service Martual if details of disassembly are needed). 5. Remove solenoid adjusting screw plug from air horn. 6. Remove solenoid plunger, air horn gasket, pump assembly, metering rods and float bowl insert. 7. Count and record the number of turns to the solenoid adjusting screw required to lightly bottom the mixture control solenoid. 8. Remove the mixture control solenoid assembly. 9. Remove float and needle. 10. Remove pump discharge plug. 11. Install accelerator pump check ball spring, P/N 17069583. SEE ILLUSTRATION 12. Reinstall pump discharge plug. 13. Reinstall float and needle.(Hook needle pull clip over float lever crossbar facing seat. DO NOT hook through holes in float lever). 14. Reinstall mixture control solenoid. 15. Reinstall solenoid adjusting screw and turn it to lightly bottom solenoid, then back out the number of turns counted during disassembly. 16. Reinstall float bowl insert, metering rods, pump assembly, air horn gasket and solenoid plunger. 17. Reinstall air horn. 18. Reinstall solenoid adjusting screw plug. 19. Reinstall air cleaner. 20. Reconnect negative battery cable.

Warranty Information:

Labor Operation: T1217

Labor Time : .9 Hour Safari and Grand Prix Models

1.1 Hour Firebird Models

SERVICE DEPARTMENT PONTIAC DIVISION GENERAL MOTORS CORPORATION

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.