my stepvan milktruck i bought in northern California, and as i drove it from the mountains down in to the central valley,
the gas gauge needle slowly rose -
it showed more and more gas, not less !
i cannot explain it - air pressure in tank or gauge ? -
but i believe , the farther away from my bitchy sister i got,
the more relief and freedom i felt
Why complain…enjoy the “more” gas.
I would run a couple of tanks of gas through the van before giving up on the gauge to see if it frees up. I had a car that hadn’t been driven for a few years. The fuel gauge was stuck but freed up after 2 fillups and has been fine since.
You might try a bottle of “Techron” on the tank, too.
I would suspect a wiring problem or a sender problem. These fuel gauges work the opposite of most other brands. The higher the resistance, the higher the gauge goes. On most other brands the gauge will go down as resistance increases. With the age of the vehicle I would suspect a bad sender. Ground the sender wire at the tank and see if the gauge goes to empty. If it does you’ll need to find a new sender.
I drove a work van to a conference, the gas gauge was backwards to all other vehicles I had driven, E was on the right and F was on the left. Thought I had a near full tank till the fuel light came on, and had to stop for gas. Maybe this is the explanation
The fuel gauge is affected by changes in the orientation of the car, especially going uphill vs downhill vs level ground. Maybe as you come downhill then transition to level driving, that causes the fuel gauge to move upwards a bit. Congrats btw on putting some distance between you and the complaining relative. That situation seems frustrating. Sounds like a cool 65 milk truck though!