2002 expedition fuel gauge starts then drops to empty

[oldgranola]

I Haven't seen this posted exactly. When I turn the ignition or start the car the fuel gauge usually goes up to where it should but then soon drops to empty and the 'check gauge' light comes on. Now it is harder to get it to go up by turning ignition on or starting the car, having to try multiple times. So this is an intermittent worsening issue. Anyone seen this? I see posts on stuck (high or empty) or totally non funcitoning fuel sending units/guages. I don't see any codes coming up on my bluetooth code reader relating to this though I do have the common tranny pressure valve issue constantly. Obviously I need to do some testing with the voltmeter and power probe. I really hope to not have to drop the tank right away, do these cars have an anti-slosh module? How best to test the gauge for this sort of issue?

 

[Number4]

I believe this is a ground issue. Do you have the P0463 code?
Most people replace the fuel pump.
However, on my ‘05, the gauge pegs empty but my ultra-gauge reads fuel levels. So I’m pretty sure it’s a ground wire to the gauge issue.