INTERMITTENT HESITATION, FUEL GAUGE FLUCTUATION, POP NOISE

SUBJECT: INTERMITTENT HESITATION, FUEL GAGE FLUCTUATION, POP NOISE ON COLD START (REPLACE TANK)

VEHICLES AFFECTED: 1989-93 "C" MODELS

Some 1989-1993 FWD DeVilles, Fleetwoods, and Sixty Specials may experience fuel tank plastic reservoir breakage that may cause the following symptoms:

0 Intermittent hesitation; rough running; lack of power.

0 Intermittent inaccurate or fluctuating fuel gage.

0 Pop noise on cold starts after an overnight soak.

The fuel tank plastic reservoir breakage is caused by a combination of reservoir material embrittlement during exposure to various fuel types and expansion and contraction of the fuel tank due to pressure/vacuum cycling. Pieces of the broken plastic reservoir may scrape the fuel tank lining material off the floor of the tank which can then restrict the fuel tank strainer and cause the driveability symptoms listed above. The broken reservoir pieces may also restrict movement of the float arm and cause fuel gage inaccuracies or fluctuation.

Service bulletin 93-6C-107 (Corporate reference number 216303R) addresses the pop noise condition and describes a repair for the pressure/vacuum cycling with a revised tank pressure control valve (TPCV). If the pressure/vacuum cycling has gone on long enough, it may have caused damage to the reservoir and will require fuel tank replacement. All service fuel tanks are built with a reservoir made of a revised material that should not become brittle and break.

To repair this condition remove the fuel tank and check the plastic reservoir. If the reservoir is broken, replace the tank pressure control valve (P/N 17089068) and fuel tank (P/N 25608430). If the reservoir is not broken and the only condition reported by the customer is the pop noise on a cold start, replace only the TPCV per Service bulletin 93-6C-107 (Corporate reference number 216303R).

WARRANTY INFORMATION

For vehicles repaired under warranty use:

Fuel Tank Replace L1260

TPCV Replace J6337

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.