Fuel Gauge Question

My '72 Demon gauge operates in a similar fashion. Maybe not to 1/2 in 30 miles, but the first 1/2 seems to drop pretty quickly. The bottom 1/2 takes a lot longer. My sending unit is an origional from a Duster '73 or newer, not sure of exact year. If you are thinking of replacing the sending unit the new replacements are much worse.
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