Engine - Reduced Cold Driveability

90oldsmobile11
SUBJECT STALL, TIP-IN LAG OR ROUGH RUNNING ON COLD
START, AMBIENT TEMP 50-80 DEGREES (DECARBON VALVES)

MODELS/YEARS 1990 CUTLASS CALAIS AND 1990 CUTLASS
SUPREME WITH THE QUAD 4 ENGINE
NUMBER: 90-T-157

CORP.REF.NO: 076001

DATE: August 1990

SECTION: 6
Some 1988-90 Cutlass Calais models and 1990 Cutlass Supreme models with Quad 4 engine, (VIN Codes A and D), may exhibit one or more of the following conditions for the first minute of cold, heavy throttle driveaway during ambient temperatures of 50-80 degrees Fahrenheit.

- Stall when put in gear
- Tip-in hesitation after immediately put in gear.
- Reduced cold engine driveability (miss, rough running or backfire).

If any of the above conditions cannot be repaired through proper service manual diagnosis, refer to Dealer Technlcal Bulletin 86-T-32 for injector harness routing and refer to Dealer Technical Bulletin 89-T-45 for 1988-89 Cutlass Calais models for the latest mem-cal. Inspect vacuum lines, especially the map sensor, for kinks or restrictions. It may be necessary to inspect the intake valves for carbon deposits.

To inspect the intake valves effectively, remove the intake manifold. If upon inspection the valves are found to have substantial deposit formation, it will be necessary to decarbon the intake valves using the Kent-Moore Carbon Blaster II, J 38375 along with adapter kit J 38743 to remove these deposits. Operating instructions are included with the tools.

Once deposits are removed, the owner of the vehicle should be advised to use fuels advertised to control deposit formation in engines.

Attached to this bulletin is an order form for the carbon blaster and adapter kit.

WARRANTY INFORMATION:

Labor Operation Number: T4674 Labor Time:
Cutlass Supreme Models 2.0 hours
Cutlass Calais Models 1.6 hours
Trouble Code: 92