I just bought my first 64 Impala. The Fuel Gauge is stays between half a tank and 3/4 a tank. Where do i start to look at what this problem might be. I see most people it is in the wiring from what I read. Mine does not have the same chateristics as everyone else. Turning on any of the other power sources do not seem to affect it at all. What should I do?
Check for a good clean ground from the tank unit to the frame...you will see the wire. remove the bolt to the frame and clean off the surfaces to bare metal, put it back on and see if that fixes the prob.
i'm a ChevyII owner, so i may be a little unfamiliar with what's available for reproduction parts etc for your car but if it were me, after checking grounds/connections etc as suggested i think i'd swap out the sender regardless. as old as it is i'd bet a nickle the fuel intake "sock" is somewhat deteriorated. the sock is located at the end of the sender... i'd also think seriously about dropping the tank and either flushing or outright replacing it. IF one is available that is.
i've owned a lot of older Chevy's in my day and one of the biggest headaches is a dirty, rusty gas tank. they do nothing but give you filter & carb problems.
my info may not be helpful to you, just a suggestion.