Oh btw,
I was wrong in saying that nobody has proven the cause of this problem
Here's an old GM service bulletin that was posted a while ago about this exact issue:
Document ID# 1284188
2000 Chevrolet/Geo Cavalier
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Inaccurate or Erratic Fuel Gauge Reading, Fuel Pump Related Driveability Concerns (Install New Fuel Tank Sender) #01-06-04-008D - (04/03/2003)
Inaccurate or Erratic Fuel Gauge Reading, Fuel Pump Related Driveability Concerns (Install New Fuel Tank Sender)
2000-03 Chevrolet Cavalier, Malibu
2000-03 Oldsmobile Alero
2000-03 Pontiac Grand Am, Sunfire
2000-01 Toyota Cavalier
with Plastic Fuel Tanks
This bulletin is being revised to add a model year and to change the Correction information as well as the part number. Please discard Corporate Bulletin Number 01-06-04-008C (Section 06 - Engine).
Vehicles built between the following VIN breakpoints:
Model
VIN
Cavalier
Y7116423 - 37248901
YS102309 - 3S150515
Sunfire
Y7116426 - 37248904
YS102393 - 3S150516
Vehicles built prior to VIN breakpoint:
Model
VIN
Alero
3C250166
Grand Am
3M655917
Grand Am
3C250181
Malibu
3M655916
Condition
Some customers may comment about inaccurate or erratic fuel gauge readings. A typical comment might be that it appears from the gauge reading that there is fuel available, yet the tank is nearly empty.
Cause
This condition may be the result of the corrosive effect of certain fuel blends on the contact surfaces of the fuel tank sender.
Correction
Important
When servicing the fuel tank module or the fuel sender, DO NOT replace both parts. Only replace the appropriate part to repair the customer's concern.
The complete fuel level sender assembly P/N 22683260 is no longer available through GMSPO. This assembly is now serviced by a fuel tank module P/N 88957239 (minus sender) and the fuel tank sender, P/N 22709333. These two parts are no longer sold as one unit and can only be purchased separately.
Dealers within the provinces of British Columbia, Quebec, New Brunswick and the State of Maine, should refer to Customer Satisfaction Campaign 00101, dated January , 2001.
When fuel gauge diagnosis in the Service Manual indicates the cause to be the fuel tank sender, replace the existing sender with a new sender, P/N 22709333, with improved corrosion resistant wiper contacts.
Important
With the availability of this new fuel level sender kit, DO NOT replace the complete fuel level sender assembly, P/N 22683260.
To insure correct installation, follow the instructions contained in the kit and the service procedure in the applicable Service Manual.
Parts Information
Part Number
Description
22709333
Fuel Tank Sender Kit
Parts are expected to be available from GMSPO on April 10, 2003.
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation
Description
Labor Time
L1197
Sender, Fuel Level (Tank Unit) - Replace
Use Published Labor Operation Time
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these 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 your GM dealer for information on whether your vehicle may benefit from the information.
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Document ID# 1284188
2000 Chevrolet/Geo Cavalier
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