1997 nissan pickup 2.4 liter auto.gas gauge drop to all most empty when driving.then i can hit a bump in the road and it will go back to normal.
You have a flat spot in the fuel level sender. If you can live with the 20, 50, whatever miles it sits on the bottom, before it pops back up, it won’t hurt anything.
Fixing it will require dropping the tank (I think), and replacing the pickup, as it’s in the tank.
I’d live with it.
The problem is with the float on the fuel pump assembly. And in order to fix this would require a new fuel pump assembly. Not cheap!
If you do decide to replace the fuel pump assembly, it’s easier to remove the six bolts that connects the bed to the frame and then tip the bed up to gain access to the fuel pump assembly on the top of the gas tank.