New subject. Gas tank & gauge. I was out enjoying a very nice sunny day in my Polara. Made a few stops for groceries & dinner. The engine kept getting harder to start after each stop. I got home & left the car half way out of garage to get into truck. 19 feet wide garage & 19 feet long car. Any way. She would not start. Gas gauge showed a 1/4 tank & battery has a 85% charge. No luck. I removed the gas line from carb & attempted to see gas going into container. Maybe a 1/2 cup & nothing more. Luck I had a full gas can for lawn mower. Fun time pouring gas into a gas cap behind license plate. Reconnected gas line after seeing gas in container. Not sure how much a 383 ci engine is supposed to have out of fuel pump. Started up & runs. Ran out of gas or poor fuel pump out put. Question? The dash gauge does not show empty. Right now with about 5 gallons of gas added. Did not move. Makes me wonder if the gauges in speedometer cluster have been tapered with. or improperly or broken gas gauge sender? The milage when purchased last year was 51,000 miles. Seems to be low for a car that went to 5 western states & hauled a trailer requiring a class 2 hitch. Ideas?
Time to check the gas gauge. Get under the car, disconnect the blue wire from the sending unit, measure resistance of sending unit to ground. Should be between 10-73 ohms. If the tank has but 5 gallons in it, the resistance likely will be a lot closer to 73, like, 55-60 ohms. Those old wiper and coil sending units are NOT linear, BTW.
Next, with the blue wire WELL away from the sheetmetal, turn your ignition switch to either Acc or ON, and measure the output voltage to ground from the wire. If its more than 6 V, then the little "regulator" behind your speedometer has shorted, and is sending too much voltage. More likely, it will read ZERO, meaning the regulator has burned out.
If the blue wire reads between 5-6 VDC to ground, then the GAUGE needs attention/replacement. Look in your FSM on how to remove the instrument cluster. You will need to replace the gauge if it fails to move after supplying between 2-6 VDC to it.
MORE likely than trouble with the gauge, your sending unit has transmogrified to a lump of metallic oxides and organo-metallic compounds. Since your gas tank is nice and low, you can easily remove the sending unit. Do so, if it reads open, or 0 ohms to ground. Realize that you MUST use an ohmmeter which will read LOW resistances ACCURATELY. Many sold today, don't.
If you read something between 10-73 ohms, the wiper may be stuck. Remove the unit, inspect it. If the float is either flooded, or missing, replace that, IFF the wiper still reads variably between 10-73 ohms. Inspect the pickup sock also. If less than perfect, replace it. They go for about $10, or did Before Trump. Now, maybe $20....
Report your findings to us here, with plenty pictures.
P.S. If your sending unit isn't working properly, your ride MAY have been sabotaged by vile Communist Agents. In this case, the thing is hopeless and should be sold to me, cheap. I will charitably come get it, as a Public Service.