Diagnosis A (Excessive Idle Vibration)

1. Warm the engine to normal operating temperature (cooling fan comes on at least twice).





2. Disconnect the upper hose from the engine mount solenoid. Attach a vacuum gauge to the solenoid.

3. With engine speed at 770 rpm or less, check for manifold vacuum.

^ If there is no vacuum, troubleshoot the engine mount control system (see section 23 of the appropriate service manual).

^ If there is vacuum, continue to step 4.

4. Disconnect the vacuum gauge from the engine mount solenoid and plug the hose port.

5. Connect a vacuum pump to the upper hose you disconnected in step 2. Apply 15 inches of vacuum for several seconds.

^ If there is a vacuum leak, inspect the hose and engine mount diaphragm.

If there is no vacuum leak, continue to step 6.

6. Turn on the air conditioning and put the transmission in Drive.

7. Have an assistant apply 15 inches of vacuum for approximately 10 seconds, then release the vacuum for 10 seconds. Repeat this several times.

^ If the level of idle vibration changes with the vacuum application, investigate other causes for the idle vibration.

^ If the level of idle vibration does not change, go to Engine Mount Replacement.