Half empty?

Never seen this happen before, but it’s one of many things that can happen to an old car. 
Can’t be driving around not knowing if I’m actually going empty so I had to investigate.

Yanked out the fuel sending unit.  I wish the fuel pump was that easy.  Then pry open the cover to get to the sending unit resistor.

Upon closer inspection I didn’t see much out of the ordinary, but I did clean up the resistor bar (it’s the orange piece) to make sure it has a good contact.


Then reassemble and throw back in to the car.  It did function properly afterwards, but as for the reason I can’t say.  Maybe there was just a small amount of corrosion to throw off the needle.