Gas gauge troubles

[casey3115]

My 1977 c10 gas gauge has been on the fritz. A few weeks ago it pegged itself way past full. It stayed that way for a few days and then one day when I started the truck it just went back down and was reading accurately again. It was fine for the next few weeks until just a few days ago. Again it pegged past full, then the next time I started it it want back to normal. Next day (today) it pegged it self again and after starting the truck a few times it seems stuck. Any ideas what I'm dealing with? I've had sending units stop working but the gauge didn't act this way.
Thanks in advance for the help

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[Obwonkonobe]

Sounds like your sender wire is either grounding or coming disconnected. Be sure it hasn't rubbed through anywhere. The power and ground wires may be bad too but I'd check the sender first since it has to run around the frame. If you aren't afraid to pop open your dash, try running a new temporary wire between the gauge and sending unit on the tank. Try to see over the frame rails and tank when checking the wire. Another option is to drop the tank and check, I replaced both my duals with the bed on, it isn't too hard.

 

[Charlie]

One thing you could do is remove gauge, clean (with sandpaper and cleaner, brake clean or alcohol) contact points on back and also the inside of the contact clips in the cluster. I have had some issues similar too this and cleaning helped a lot.