STALLING, LOSS OF POWER (REVISED LIFTER)

SUBJECT: STALLING, LOSS OF POWER (REVISED LIFTER)

VEHICLES AFFECTED: 1989-92 GEO METRO

CONDITION:

--------- Some 1989-92 Metro's, Chevrolet Sprint, Pontiac Firefly built before VIN breakpoints listed below may exhibit a stall or loss of power condition shortly after starting the vehicle. This condition may be aggravated by revving of the engine by the customer immediately after start-up.

CAUSE:

----- High pressure in the hydraulic lifter assemblies may result in valves not closing completely due to the inability of the lifter to bleed oil quickly enough during the cold start cycle.

CORRECTION:

---------- 0 Check and reset if necessary, engine timing and throttle position sensor (TPS) settings to Service Manual specifications.

0 Check valve spring length and force to Service Manual specifications and replace if necessary, making sure to inspect for proper installation of the valve spring seats prior to reassembly.

0 Check camshaft wear by measuring camshaft lobe height per the service Manual procedure. If the camshaft lobe height is less than the minimum limit, replace the camshaft.

0 On ALL 1989,1990, And 1991 models, and on 1992 models built prior to the specified VIN breakpoints (listed below), replace the hydraulic lifter assemblies with a revised design lifter, P/N 17106263, per Service Manual procedures. (Engines used in 1992 models beginning with the specified VIN breakpoints, and all 1993 models have been built using the revised design lifter assembly incorporating a faster bleed down rate.)

VIN Breakpoints:

2C1MR2160N6761709 (3DR and 5DR Models) JG1MR3362NK211827 (Convertible Models)

Drain engine crankcase, replace oil filter, and refill using SAE 5W-30 Grade, API service SG, Energy Conserving II Oil.

WARRANTY INFORMATION:

For vehicles repaired under warranty use:

Labor Time: 5.8 Hrs. Add: 0.3 Hr. (Vehicles with A/C)

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.