Sender unit defective sender unit disconnected wiring problem dash to sender rear dash connector problem defective guage
You have a ground from the oil sender unit to the gauge. This is how you check a gauge. ground out the wire at the sender and it pegs out the gauge.
Wiring or sender unit in the tank.
The fuel gauge sending unit is located inside the fuel tank.
Sounds like a wiring or sender unit problem. Ground wire at sender unit, see if it stays steady. If it still jumps around, wiring/gauge problem. If it stays steady, sender unit should be replaced. Good idea to do an oil pressure test as well.
the problem with your fuel gauge may be normal as my Toyota Camry does this also. On the temperature guage it could be a bad temp. sender unit, a bad gauge, wiring between the sender unit and the guage. Disconnect the connector at the sender under the hood (normally located in the thermostat housing) and see if the temp guage reads zero. If it does, it's the temp sender unit.
Temp sender on the 289 should be located at the front of the intake manifold. Source: www.AverageJoeResto.com
Fuel gauge not working on Audi 80 1986. I've tested the wires (with a test pencil) that lead to the sender unit and there is no power. I can't find a fuse for this circuit either.
Its normally the sender. Take the wire off the sender (on the tank) and earth it. Turn the ignition on. If the guage rises the sender needs replacement. If not then its more likely to be a wiring fault than the gauge itself
fuel gage sender unit is faulty
check for broken wire from fuel sender unit in fuel tank to gauge. check fuel sender unit for proper operation. float may be stuck in the tank then check fuel gauge
might be a bad fuel sender unit or BCM