ENG. MAY INTERMITTENTLY STALL CHECK FOR RESIDUE ON THROTTLE

MODEL AND YEAR: 1985-87 CAMARO, CAVALIER, CELEBRITY WITH 2.8L P.F.I. ENGINE 1987 BERETTA, CORSICA WITH 2.8L P.F.I. ENGINE

TO: ALL CHEVROLET DEALERS

Some 1985, B6 and 87 vehicles equipped with 2.8L V-6 P.F.I. engines may experience a stall after start with a warmed up engine or a stall during deceleration.

This condition may be caused by residue accumulating inside the throttle body bore behind the throttle plate and limiting air flow past the throttle plate in the idle position.

To diagnose this condition, perform the following steps:

1. Measure minimum idle speed using procedures defined in Section 6E3 of the service manual.

2. If the minimum idle speed is less than what is specified below in the minimum idle speed chart, proceed to Step 3. Otherwise, perform activities defined in the service manual under Section 6E3, Section B - Rough, Unstable or Incorrect Idle, Stalling.

CHART - MINIMUM IDLE SPEED

Year Model Minimum Idle Sneed Specification *

1985-86 Camaro 550 + or - 50 RPM in drive (A/T) Cavalier 650 + or - 50 RPM in neutral (M/T) Celebrity

1987 Camaro 550 + or - 50 RPM in drive (A/T) 650 + or - 50 RPM in neutral (M/T)

1987 Beretta 550 + or - 50 RPM in drive (A/T) cavalier 675 + or - 50 RPM in neutral (M/T)

* Engine should be at normal operating temperature.

3. Remove the negative battery terminal.

4. Remove mass airflow duct at throttle body.

5. Cover TPS and IACV to protect from overspray.

6. Clean the throttle body bore in the area behind the throttle body. Use a shop towel with GM Top Engine Cleaner, P/N 1052626, or AC-Delco Carburetor Tune-Up Conditioner, P/N X66-A, or equivalent that does not contain methyl ethyl ketone.

It should be noted that what appears to be a small amount of accumulation can be enough to limit air flow.

7. Install mass airflow duct.

8. 1987 model year vehicles built after the following V.I.N. breakpoints will not require checking and resetting of minimum idle speed.

1987 MODEL YEAR V.I.N. BREAKPOINTS ------------------------------------ Model V.I.N. ----- ------ Celebrity G146967 6181561 9165041

Cavalier 7160371 J175417 K134154

Beretta Corsica Y106246

Camaro Nl39297 L123884

Recheck minimum idle speed on 1985-86 vehicles, and 1987 vehicles built prior to the above V.I.N. breakpoints. Adjust if necessary to specifications defined in step 2 above.

Labor Operation Number: T1205

Labor Time : .5 Hour

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.