Where can you buy just the gasket for 2005 GV250 fuel level sender?

The fuel filter is mounted on the side of the actual fuel tank under the vehicle and is part of the fuel sender/fuel level sensor unit. I think it is mounted on the drivers side, (left side). The bad news is that you will need to replace the filter, sender and fuel level senor as one piece. You can't replace the filter separately.

No, it's likely the gas lines, or yes the pipes coming out of sending unit to the lines going to or coming back from engine but yes part of the sending unit itself or the gas lines right there until it turns to rubber. These lines could be bronze welded but not while fumes of fuel exist so you put fumes from car exhaust through it after removing fuel pump and shaking that to get the rust out and check the filter at the botttom of pick up tube under fuel pump just watch out for the gas level indicator float as you remove fuel pump from tank, see my other post here tonight for more info.

the fuel level sensor is a float off the side of the fuel sender. over time these floats can become weak at the pivot point and read inaccurately. fuel sender should be replaced to correct this problem

If it seems steadier with some certain level of fuel in the tank, then a section of your level sender has failed; if it doesn't, then one or the other end of the variable resistor is no longer making solid contact.

In either case, you probably need a new level sender which is located in the fuel tank and that may have to be removed in some vehicles for access.

Some vehicles the sender can be replaced without removal of the tank through an access panel under the floor of the trunk or under the back seat, depending on where the tank is located.

As I do in most cases whether you like to DIY or have repairs done, having a copy of a service manual on hand costs $20-25 US and they can be had on line or at auto parts stores.

I prefer Haynes:

Haynes 2005 Malibu manual

there is at minimum a fuel level sender and a fuel pump inside there. they install through a common hole on the top. the sender has a wire, the pump has power in and fuel out. so there are "connections"
for that if that is what you mean. dropping a tank is a serious and possibly dangerous task, do not undertake it yourself.

it is inside the gas tank, attached to the fuel pump. you might be better off buying an entire new
pump/sender unit and swapping it in when you remove the old one. Both are now 13 years old and past the end of their designed life. buy a new ring gasket for the top of the tank and do it too.

There is a TSB for this issue ( TSB 08-2-9 ).

The problem is high sulfur content fuel will cause a problem with the fuel level sending unit, and cause it to read incorrectly.

The 2 times I had this happen, I was not at my normal brand fuel ( had it happen with Shell fuel both times ).

I fueled at 1/2 tank with my normal brand, and then after another 1/2 tank fueled again, and the problem went away.

If you want, the TSB lists new revision fuel level senders, that you can drop the fuel tank, and replace your exiting one with to cure the problem.

The correct P/N depends on your truck cab & bed config, and options

PART NUMBER PART NAME
8L3Z-9A213-E Kit - Fuel Sender 2006 starting 12/8/2005 through 2008 - FFV-26 Gal Tank - 126/132 WB
8L3Z-9A213-F Kit - Fuel Sender 2006 starting 12/8/2005 through 2008 - FFV-30 Gal Tank - 139 WB
8L3Z-9A213-G Kit - Fuel Sender 2006 starting 12/8/2005 through 2008 - FFV-27 Gal Tank - 145/151/163 WB
8L3Z-9A213-H Kit - Fuel Sender 2006 starting 12/8/2005 through 2008 - FFV-36 Gal Tank - 145/151/163 WB
8L3Z-9A213-A Kit - Fuel Sender 2004 through 2008 - Gas-26 Gal Tank - 126/132 WB
8L3Z-9A213-B Kit - Fuel Sender 2004 through 2008 - Gas-30 Gal Tank - 139 WB
8L3Z-9A213-C Kit - Fuel Sender 2004 through 2008 - Gas-27 Gal Tank - 145/151/163 WB
8L3Z-9A213-D Kit - Fuel Sender 2004 through 2008 - Gas-36 Gal Tank - 145/151/163WB

There is a TSB on high sulfur fuel usage, and how it impacts the fuel level resistance.
If you change fuel, it might start working again. The TSB is : ERRATIC FUEL GAUGE OPERATION TSB 08-2-9

Publication Date: January 22, 2008
FORD: 2004-2008 F-150
LINCOLN: 2006-2008 Mark LT


ISSUE:
Some 2004-2008 F-150 and 2006-2008 Mark LT vehicles, built before 12/3/2007, may exhibit erratic fuel gauge operation or illuminated malfunction indicator lamp (MIL) with diagnostic trouble codes (DTCs) P0460 or P0463, and/or Instrument Cluster Module DTC B1201. This may be caused by sulfur contamination in the fuel causing an open or high resistance in the fuel level sender.

ACTION:
Follow the Service Procedure steps to correct the condition.

SERVICE PROCEDURE

Install a new fuel level sender following the service procedure instruction sheet provided in the fuel sender kit.

PART NUMBER PART NAME
8L3Z-9A213-E Kit - Fuel Sender (2006 starting 12/8/2005 through 2008 - FFV-26 Gal Tank - 126/132" WB )
8L3Z-9A213-F Kit - Fuel Sender (2006 starting 12/8/2005 through 2008 - FFV-30 Gal Tank - 139" WB)
8L3Z-9A213-G Kit - Fuel Sender (2006 starting 12/8/2005 through 2008 - FFV-27 Gal Tank - 145/151/163" WB
8L3Z-9A213-H Kit - Fuel Sender (2006 starting 12/8/2005 through 2008 - FFV-36 Gal Tank - 145/151/163" WB
8L3Z-9A213-A Kit - Fuel Sender (2004 through 2008 - Gas-26 Gal Tank - 126/132" WB
8L3Z-9A213-B Kit - Fuel Sender (2004 through 2008 - Gas-30 Gal Tank - 139" WB
8L3Z-9A213-C Kit - Fuel Sender (2004 through 2008 - Gas-27 Gal Tank - 145/151/163" WB
8L3Z-9A213-D Kit - Fuel Sender (2004 through 2008 - Gas-36 Gal Tank - 145/151/163"WB



WARRANTY STATUS:
Eligible Under Provisions Of New Vehicle Limited Warranty Coverage And Emissions Warranty Coverage
IMPORTANT: Warranty coverage limits/policies are not altered by a TSB. Warranty coverage limits are determined by the identified causal part.

OPERATION DESCRIPTION TIME
080209A 2004-2008 F-150, 2006-2008 Mark LT: Install New Fuel Level Sender, Includes Time To Remove And Install Fuel Tank (Do Not Use With 9002A, 9002A4, 9002A6) 1.9 Hrs.

DEALER CODING
BASIC PART NO. CONDITION CODE
9A299 42

First...this is where the pump is (gas tank) on the engines listed:



Illustrating fuel pump and sending unit sensor (3) on 1999-2005 4.8L, 5.3L, 6.0L Engines


Removal & Installation

1. Before servicing the vehicle, refer to the Precautions section.
   
2. Remove or disconnect the following:
   
   • Negative battery cable
     
3. Relieve the fuel system pressure.
   
4. Drain the fuel tank.
   
5. Remove or disconnect the following:
   
   • Fuel tank
     

WARNING Do not handle the fuel sender assembly by the fuel pipes. The amount of leverage generated by handling the fuel pipes could damage the joints.

• Fuel sender assembly retaining ring using a fuel tank sending unit wrench. Remove the fuel sender assembly and the seal. Discard the seal.
  

Note the position of the fuel strainer on the fuel sender. Support the fuel sender assembly with one hand and grasp the strainer with the other hand. Pull the strainer off the fuel sender. Discard the strainer after inspection. Inspect the strainer. Replace a contaminated strainer and clean the fuel tank.

• Fuel pump electrical connector
  
• Electrical connector retaining clip from the fuel level sensor
  
• Sensor electrical connector from under the fuel sender cover
  
• Fuel level sensor retaining clip
  

Squeeze the locking tangs and remove the fuel level sensor.

Remove the fuel pressure sensor.

To install:

1. Install or connect the following:
   
   • Fuel pressure sensor
     
   • Fuel level sensor
     
   • Sensor retaining clip
     
   • Electrical connector to the fuel level sensor
     
   • Electrical connector retaining clip to the fuel level sensor
     
   • Fuel pump electrical connector
     
   NOTE Always install a new fuel strainer when replacing the fuel tank fuel pump module.
   
   
   • New fuel strainer in the same position as noted during disassembly. Push the strainer on the bottom of the fuel sender until the strainer is fully seated.
     
   • New seal on the fuel tank
     
   NOTE The fuel pump strainer must be in a horizontal position when the fuel sender is installed in the tank. When installing the fuel sender assembly, assure that the fuel pump strainer does not block full travel of the float arm.
   
   
   • Fuel sender assembly into the fuel tank
     
   • Fuel sender assembly retaining ring
     
   • Fuel tank. Install the fuel tank strap attaching bolts. Tighten the bolts to 30 ft. lbs. (40 Nm).
     
2. Refill the fuel tank. Install the fuel filler cap. Connect the negative battery cable.
   
3. Turn the ignition ON for 2 seconds.
   
4. Turn the ignition OFF for 10 seconds.
   
5. Turn the ignition ON.
   
6. Inspect for fuel leaks
   

Suspect faulty fuel level sender. The powertrain control module (PCM) monitors the signal circuit of the fuel level sender in order to determine fuel level.