Ignition/Exhaust - Idle Vibration

Article No.
95-10-11

05/22/95

VIBRATION - FELT IN SEAT AND STEERING WHEEL AT IDLE - 4-DOOR VEHICLES BUILT 11/28/94 THROUGH 2/11/95

LIGHT TRUCK:
1995 EXPLORER

ISSUE:
A vibration may be felt in the seat or steering wheel on some vehicles. This vibration can be felt under the following conditions:

^ Vehicle in "DRIVE"

^ Brake depressed

^ Climate control system "OFF"

^ Idle speed normalized at 720 rpms

This may be caused by the muffler outlet assembly having the same resonant frequency as the engine spark plug firing frequency.

ACTION:
Replace the existing muffler outlet assembly with a dampened muffler outlet assembly and add an additional tailpipe hanger. This will change the resonant frequency 3 Hz below the engine spark plug firing frequency. Refer to the following Service Procedure for details.

SERVICE PROCEDURE

1. Raise vehicle and remove the muffler-to-catalyst attaching bolt.

2. Disconnect lateral shock from rear axle housing.

3. Disconnect rear stabilizer bar connection.

4. Remove tailpipe hanger rod from insulator.

5. Remove muffler and tailpipe assembly.

6. Install additional tailpipe hanger bracket (F57Z-5260-C) to outside of frame, in holes provided, with two (2) nuts (N620481-S2) and torque to 22 +/- 3 N-m (16 +/- 2 lb-ft.).

7. Install muffler and new tailpipe assembly (F57Z-5230-H).

8. Insert muffler body hanger rods into insulators.

9. Insert tailpipe hanger rods into insulators.

10. Reattach muffler assembly to catalyst, ensuring the gasket is in the proper position and torque bolts to 40 +/- 6 N-m (29 +/- 4 lb-ft).

11. Start vehicle and check exhaust system for leaks.

Parts Block:

Parts Block

OTHER APPLICABLE ARTICLES: NONE

WARRANTY STATUS: Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage

OPERATION DESCRIPTION TIME

951011A Replace Muffler Assembly 0.7 Hr.
And Install Additional
Hanger

DEALER CODING
CONDITION
BASIC PART NO. CODE
5230 79

OASIS CODES: 403000, 703000, 703100