I have a camaro 91 RS-305 (V8), I have a problem with the fuel needle, whenever the fuel tank is full, the fuel needle sticks to "F" position and does not move, once the fuel level gets lower, the fuel needle starts moving left/right continuously while driving the car without giving right indication about the fuel level.
Is this a problem with Fuel Gauge it self or something wrong with fuel floater, or fuel sending unit? Any idea what to do?
Thanks

 

The first thing you should do is disconnect the signal wire from the sending unit. IIRC, the gauge should read full all the time with no signal. (It will either read full or empty and not change)

You should disconnect the wire as close to the gauge as possible, in case the signal wire is shorting to ground along its path. The sender uses a float in the tank to move a variable resistor, which provides a ground signal to the gauge. Again, I am pretty sure that full resistance gives you a full tank reading, and full ground gives you a reading of empty, but it could be the other way around.

You can check this by getting about a 100K potentiometer from Radio Shack and connecting it between the gauge and ground with the tank signal wire disconnected. Adjusting the potentiometer will vary the needle position accordingly (with the ignition on). That will tell you whether or not your gauge is working properly. If it isn't, replace the gauge. If it is, you have to troubleshoot your sender and signal wire.

 

Thanks,,I'll try that