Fuel guage bounces?

[JamesSam]

My guage moves while driving but it is obviously related to the fuel moving in the tank(moving the bob) because of inclines or bumps on the road etc. Old guages.

 

[DRW65]

My 86 K1500 fuel gauge needle would swing all over the place if the tank was less than full. Replacing the gauge solved the problem. Gauges from LMC seem to be of good quality, course all are made overseas.

 

[KatmanDo]

On my 78 that had been setting for 7 or so years, I went through the fuel system and only replaced the pick-up sock and fuel pump. The arm on the sender was really crusty. Sprayed it down with WD-40 and bench tested so that it read the full 90 ohms swing.
My gauge bounces but accurate when stopped. Also read somewhere here, that there was a type of fluid dampening withing the arm to slow all the action down.
That may be what we all are seeing.

 

[squaredeal91]

Just got my resistor in the mail. Not sure when I'll use it but I at least have it for when it's time.