Oldsmobile/Buick Repair: nonworking gas gauge & non working speedometer, gas gauge, fuel meter

Question
have 92 olds custom cruiser sw. gas gauge not working. Is there a fuse somewhere for it? Also speedometer not working. Will go over like it wants to work then flys allway to right side & u can hear it spinning.Can u help? Thank u 4 your time

Answer
What kind of work of anykind what-so-ever has been performed on the vehicle. I need to know everything that was done.

Usually the fuel meter in the gas tank is faulty and or look for a single black ground wire that comes from the center of the gas tank where the fuel meter goes and make sure it is attached to a good ground source. I have found many broken or rusted off and just laying beside the fuel tank.

Is the speedometer ANALOG or DIGITAL display ?.