Vehicle on Ground, Engine Running

HOOD STOP(S) AND LATCH ASSEMBLY (1991-1994 VEHICLES)

Check hood for flutter at idle (in drive "D" for automatic transaxle, or neutral for manual transaxle). Adjust hood stop(s) to fit hood with fenders. If hood still flutters, lower the hood latch assembly as necessary to eliminate condition.

ENGINE POSITIVE CRANKCASE VENTILATION VALVE (PCV) (1991 VEHICLES)

Check PCV for shuttle/flutter. Listen for noise at the PCV valve with engine at idle and transaxle in neutral. if a noise is suspected, pinch off the hose and listen for a change in sound. Replace the PCV valve if the noise disappears.

BRAKE POWER BOOSTER CHECK VALVE (1991 VEHICLES)

CAUTION:
THE VEHICLE'S BRAKING SYSTEM IS IMPAIRED WHEN THE BRAKE BOOSTER CHECK VALVE HOSE IS PLUGGED. DO NOT OPERATE THE VEHICLE WITH A PLUGGED BRAKE BOOSTER HOSE OR THE CHECK VALVE REMOVED.

Check the power brake booster check valve for a high-pitch flutter or rattle noise. Listen at the booster, outside the vehicle, for an audible sound and inside the vehicle near the instrument panel, while having another technician pump the brakes. if a noise is present, remove the hose from the check valve and plug it. Replace the cheek valve if the noise disappears.

IMPORTANT:
Rattle noises can also occur in the instrument panel and are frequently heard from inside the vehicle. it will be necessary to isolate the noises using the brake booster check valve diagnostic information provided.

FRONT AND REAR TRANSAXLE MOUNT ASSEMBLY REPLACEMENT (FOR DOHC [LLO]/AUTOMATIC TRANSAXLE) (1991 VEHICLES)

After completing the preceding steps, and if the vibration condition has not been corrected, replace the front and rear transaxle mount(s) with service replacement parts.

Front Transaxle Mount Replacement (P/N 21011341)

Refer to "Transaxle Front Mount" in the "Powertrain Mounts Service Manual" for removal and installation procedures.

Rear Transaxle Mount Replacement (P/N 21011722)

Refer to "Transaxle Rear Mount" in the "Powertrain Mounts Service Manual" for removal and installation procedures.

DIAGNOSTIC EVALUATION (1991-1994 VEHICLES)

NOTE:
Minimum Idle Speed (TBI-MFI) adjustments are set at the factory and MUST NOT be tampered with to alter minimum or maximum engine idle speed. Improper adjustment of the idle speed screw can cause false PCM codes, idle instability and automatic transaxle shift concerns, etc.

After all checks have been completed and a vibration concern is not corrected. test the engine on the service basic analyzer (SBEA or equivalent) diagnostic system. Verify that cylinder power contribution, compression spark plug gap, spark plug wires, fuel pressure, fuel quality, DIS module operation/grounding, vacuum leaks, PCM coolant sensor, air temperature sensor, MAP, EGR injector(s), etc. are not causing an intermittent cylinder misfire.