2002 Buick LeSabre how repair the part that tells you how much gas youn have in the car

I believe your asking about the fuel sending unit? That unit sends the signal to the fuel gauge telling how much fuel is in the tank. It is usaully inside the fuel tank along with the fuel pump. It would be a good idea to change both of them if you are planning on doing the job.

Really easy to change the whole pump.. It is located in the trunk under and panel. Mine did this as well. 4x in its 270,000+ miles. I change it myself in less than a hour and the gauge begins to work again.