Need help gas gauge going crazy

[k51977blazer]

Little background info 1976 k5 blazer last owner replaced wiring harness,gas tank,lines, I replaced the printed circuit,The truck sat for awhile 5 to 8 years, now for the problem I put gas in it gauge moves I start it gauge stays where it should be I drive it and holy shit the gas gauge does circles when the gas settles it goes back to where it should be I have power and good ground is this a gauge issue or a sending unit isssu please help and thanks every one

 

[Wes Harden]

Sounds like there might be something in the tank moving the float as you accelerate and brake. Just a guess.

 

[k51977blazer]

That’s what I was thinking

 

[dyeager535]

Damping of the float is done at the gauge.

I verified this for my own curiosity when I replaced my fuel pump a few weeks back. Float moved by hand from full to empty far faster than would ever happen in a tank, gauge still slowly responds.