From the SERVICE MANUAL:
FUEL LEVEL SENSOR
DESCRIPTION
The level sensor is attached to the side of the fuel
pump module (Fig. 2). The level sensor consists of a
float, an arm, and a variable resistor.
OPERATION
As the fuel level increases, the float and arm move
up. This decreases the sending unit resistance, causing
the fuel gauge on the instrument panel to read
full. The fuel level sensor (fuel gauge sending unit)
sends a signal to the BCM and the BCM sends the
signal over the PCI bus circuit to the PCM to indicate
fuel level. The purpose of this feature is to prevent
a false setting of misfire and fuel system
monitor trouble codes if the fuel level is less than
approximately 15 percent of its rated capacity. It is
also used to send a signal for fuel gauge operation
via the PCI bus circuits.
FUEL TANK DESCRIPTION
The fuel tank is constructed of a plastic material.
Its main functions are for fuel storage and for placement
of the fuel pump module (Fig. 3). The tank is
made from High density Polyethylene (HDPE) material.
Could be the float arm, could be that its PLASTIC and the tank is starting to derom- have a look under the PT if you can.
