POOR DRIVEABILITY/STARTABILITY DIAGNOSIS R/R PCV HOSE. Pontiac Optima (Canada) 1990

For 1990-2009 cars

# POOR DRIVEABILITY/STARTABILITY DIAGNOSIS R/R PCV HOSE

#### Subject: POOR DRIVEABILITY OR STARTABILITY WHEN COLD STARTING (DIAGNOSE, REMOVE/REPLACE PCV HOSE)

#### Models Affected: 1988-90 LEMANS W/1.6L

CONDITION: Some 1988-1990 Pontiac LeMans may experience rough engine idle quality or poor driveability during certain cold climatic conditions, high humidity and extremely cold temperatures.

CAUSE: Moisture may collect and freeze in the PCV system vacuum source hose and restrict normal PCV operation. This may allow crankcase moisture to be vented through the air cleaner into the throttle body injector instead of being pulled in through the intake manifold.

DIAGNOSIS: Inspect the PCV vacuum hose (Figure 1) . If the hose does not maintain a positive downward flow to the intake maifold (if a low spot is detectable) then th hose may be too long.

#### PROCEDURE:

1. Remove the hose from the vehicle and measure the length.

2. If the hose does not measure 160 mm, cut the hose to length of 160 mm.

3. Reinstall the hose on the vehicle.

4. Verify that the hose maintains a positive downward flow to the intake manifold. If the hose does not maintain a positive downward flow (sagging condition) then additional length must b removed from the hose.

Labor Operation: T1661

Labor Time: .3 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.