Fuel Guage Goes Up Then Partly Fades -- 72 Swinger

I agree that the resister test would do alit to prove things out.

As for the gauge climbing then falling, I too have never seen that. I recently had a mechanical IVR failure and decided to go with the RT-eng IVR. the fuel gauge works just as with the mechanical IVR. also in your video the speed that it climbs seems too fast.

If you can easily reach the back side of your cluster you can clip a lead on to the correct post and read the voltage from key on to settling down.

FYI, Mechanical and the RT-Eng will give a digital multimeter a run for it's money trying to read a steady voltage.

Since to is on or off it is either 12v or 0 v and the meter will fluctuate drastically.

If you can get an analog volt meter you could watch the needle fluctuate. A test light will work as well for functionality just not for voltage.