For 1990-2009 cars

# ENGINE DRIVEABILITY CALIBRATION SPECIFICATIONS

1983 5.0L (CODE Y) ENGINE DRIVEABILITY VEHICLES AFFECTED: SOME PASSENGER CARS EQUIPPED WITH THIS ENGINE AND NON CLOSED LOOP EMISSION CONTROL SYSTEMS SOME 1983 PRODUCTION VEHICLES EQUIPPED WITH THE 5.0L (CODE Y) ENGINE MAY EXPERIENCE CUSTOMER DRIVEABILITY COMMENT. THE MAJORITY OF THESE COMMENTS CAN BE CORRECTED BY ENSURING THE ENGINE IS SET UP TO THE CALIBRATION SPECIFICATIONS ON THE TUNE-UP LABEL. IN PARTICULAR, PAY ATTENTION TO THE FOLLOWING: 1. ENSURE SPARK TIMING IS AT 12 DEGREES BTDC. 2. ENSURE FLOAT LEVEL IS NOT LOWER THAN 10.3 MM (13/32 INCHES). 3. ENSURE NO VACUUM LEAKS. 4. CHECK IDLE MIXTURE USING PROPANE ENRICHMENT PROCEDURE. THE SPECIFICATION IS 40 + 30 ENRICHED RPM. THE MINIMUM ALLOWED IS PREFERRED. 5. STALL COMPLAINTS BELOW 70 DEGREES F ON CLEANER TEMPERATURE CAN BE COUNTERACTED BY REDUCING THE PRIMARY VACUUM BREAK SETTING TO 20 DEGREES FROM THE ORIGINAL 24 DEGREES SPECIFICATION.

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.