Does anyone know why my fuel gauge drops down to empty after 50 miles after filling up the tank. Will the low gas light will come on when tank is almost empty or should i just refill after a certain amount of miles.

 

I had a similar problem. Fill up and it would go to the top . Drive fifty miles and bam, down to zip, zero. Tried to make the sender unit work by taking it out and moving the float up and down but the pot was just bad. The low light still worked. Its a seperate thermistor. But I never could get myself to trust it so I did the junk yard trip. I also patched in a working unit from another car to prove the existing unit was bad and not a wiring problem. Long way to say, yes, the low lite should stillwork. Seperate circuit. Seperate parts.