I would check the ground on the fuel sending unit
it might be a fuse
It could be the fuse, but mine is because the floater that measures for the gauge is stuck.
The ranger has a fuel sending unit inside the gas tank. These are notorious for going out. Only way to change it is to drain and drop the gas tank or remove the bed. The sending units that I have been looking at cost about $100
Looking at my Chilton repair manual engine wiring schematics ( with a magnifying glass ) for the 1992 Ford Ranger it looks like fuse # 16 is a 15 amp fuse for the fuel gauge
The Sears Ranger 105-20 16 gauge shotgun came out in the 1930s. The Sears Ranger shotgun has a 26-inch barrel.
Your gauge could be bad but more than likely it is the temperature sending unit. It is a fairly inexpensive thing to fix.
Bad oil pressure sending unit?
If not losing coolant Could be thermostat slow to respond to temperature changes Could be gauge itself check temperature with thermometer Remember gauges are just a guide they are not gospel and sometimes malfunction
The fuel gauge could be getting improper signals from the fuel sensor. The sensor is located inside of the fuel tank.
According to my Chilton repair manual , fuse # 16 is a 15 amp fuse for the fuel gauge on a 1994 Ford Ranger
One scenario could be that the sending unit for the gauge on the engine is bad. Try to locate it and replace it if it is corroded and check the wiring to it also.
< $100