And at the end of the day, it must be said the gauge is totally dependent on the sender. When I say totally, I mean that. I've found the AD fuel gauge to be as accurate as it needs to be. In fact, after testing 3 of them (from different years) some time ago I could not see any difference at all. I even resorted to making a paper scale with marks separated by 1/16" in an arc to better see any variations. But the senders? The original equipment senders were at best fair and honestly speaking they were designed to fail. They sold for about $7 at the dealership parts depts and they were meant to last about 5 years at the most. Of the senders available today there is only one of them I've seen worth even considering. It is sold by an eBay seller whose id is renbusan. Here is the 0-30 ohm sender he sells: https://www.ebay.com/itm/261122347319?hash=item3ccc1ad137:g:FBgAAOSwpPVgBuwZ&vxp=mtr
That sender isn't perfect, but it is pretty darn close to it. Why? Because it is a completely different design. It was designed and built in Taiwan by somebody who knew what they were doing. The wiping plane is flat, the sensing fingers are metal which connect to a special arc shaped poured-in-place resistance compound and the body is nylon. So the only thing that will wear out is the wiper button...and those typically last a good while. I've spent over 10 years studying fuel gauge senders off/on and the whole arena is quite challenging. I have designed and made one which is very close to ideal, however to make enough of them to sell will cost more than I'm prepared to spend at this time.
As I've posted here before, some of the senders I have seen are pure 100% junk. Take a look below. This was sold by a popular vendor I won't mention by name as a 0-30 ohm unit. It began life as a 0-90 ohm unit onto which the assembler dribbled hot solder until he/she had reduced resistance by 60 ohms. That is the sort of sending unit that makes people "think" their AD fuel gauge is bad.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
