ENGINE MAY INTERMITTENTLY STALL (CHECK FOR RESIDUE)

ENGINE MAY INTERMITTENTLY FAIL TO RUN

VEHICLES AFFECTED: 1985-1988 'P' W/ 2.8L (VIN 9) -----------------

Some 1985-88 Fieros equipped with a 2.8L V-6 engine may fail to run after start with warmed-up engine or during deceleration, or experience an extended crank time during engine start. These conditions may be caused by residue accumulating inside the throttle body bore, behind the throttle plate, and limiting the air flow past the throttle plate in the idle position. To diagnose this condition, perform the following steps:

1. Measure minimum idle speed at normal operating temperature, using service procedures as defined in Section 6E3 of the Service Manual.

2. If the minimum idle speed (as measured in Step 1) is less than 762 RPM in drive (automatic transmission) or 862 RPM in neutral (manual transmission), then proceed to Step 3. Otherwise, perform service procedures as defined in Section 6E3 of the Service Manual under rough, unstable or incorrect idle stalling.

3. Remove the negative battery terminal.

4. Remove the rear air intake duct at the throttle body to the air cleaner.

5. Cover the 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 052626 or AC Delco carburetor tune-up conditioner, P/N X66-A or equivalent that doesn't contain methyl ethyl ketone.

7. Remove overspray cover from TPS and IACV.

8. Install rear air intake duct at the throttle body to the air cleaner.

9. Install negative battery terminal.

10. Recheck minimum idle speed to specification defined in Step 2, and adjust if required. The maximum allowed idle speeds are 838 RPM in drive (automatic transmission) and 938 RPM in neutral (manual transmission).

Warranty Information:

Use applicable Labor Time and Operation Code.

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.