needs a fuel level sending unit 100 percent sure
this is a problem with the gauge cluster. very common problem. you may also notice the neeedles moving very erratic at times. it is a common problem with s10/jimmy/blazers/sonoma
inertia
with a full tank of gas the gauge will drop to "E" then after a few seconds it will jump back to correct reading.
check your ground wire to the gauge
Your gauge could be bad but sometimes the floats in the gas tank get holes in them and fill with gas. this causes the float to stay at the bottom and your gauge to read empty. U might also check the wiring from the sender at the fuel tank to the gas gauge itself.
fuel sending unit broken wire or gauge is bad
bad sending unit
no power at the sending unit.
Try to see if there is a common ground wire to these 2 gauges. If there is make sure it is grounded to a clean dry grounding site and see if this helps.
bad temp sender usually. Bad gauge rarely.
The sending unit is probably bad, not unusual.
fuel gauge on my 99 buick centry custom stays at full , then drops to empty. Is there a fuse or relay that i can have my neighbor look at it