METALLIC BUZZ OR RATTLE NOISE INSTALL CLAMP/REPOSITION PIPE

Subject: METALLIC BUZZ OR RATTLE NOISE (INSTALL CLAMP/ REPOSITION A.I.R. PIPE)

Models Affected: 1991-92 FIREBIRD MODELS WITH 5.OL OR 5.7L ENGINE

CONDITION:

--------- Some 1991-92 Firebird models with 5.OL or 5.7L V-8 engines (RPOs LB9 or L98) and dual catalytic converter exhaust systems (RPO N10) , may exhibit a metallic buzz or rattle that is most apparent during low speed/low load type operations.

CAUSE:

----- The two causes indicated below may result in a metallic buzz/rattle noise:

Cause 1: Intermittent contact between the exhaust pipes just forward of the catalytic converter.

Cause 2: Air injector reactor (A.I.R.) pipe in contact with the toe pan to the front of the dash trim flange.

CORRECTION:

----------

Correction 1: Install clamp, P/N 10041052, to the inboard exhaust pipe just rearward of the exhaust pipe to the catalytic converter extension pipe. Weld as illustrated in Figure 1.

Correction 2: Reposition A.I.R. pipe to insure clearance of approx- imately 25 mm (1 inch) between the pipe and trim flange (reference Figure 2).

Part is currently available from GMSPO.

Warranty Information:

Labor Operation: T1851 Labor Time: .3 Hr.

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.