I just picked up a '70 coupe last week and gas gauge is acting weird.. when I drive it the needle floats back and forth on the gauge. Could it be a sender problem or is the gauge bad? How hard is it to change out the gauge?

Thanks!!
Ken

Try cleaning the contacts of the wires going to the sender unit. It could be a bad ground or a worn rubbing block on the sender unit. The sender unit just reads resistance, so any "opens" will read as a full tank.

If you have to replace the sender, it's not too expensive and relatively easy after you drain the gas out of the tank. You should replace the o-ring if you pull the sender out.

Mine acts up once in a while after sitting, but usually is self healing. There is a picture of the sender unit on our website "Corvette rebuild".