Any ideas? My fuel guage sometimes reads empty and gas light comes on when there is plenty of gas in truck....If restarted, guage reads accurate again. frustrating...

Bad ground wire. Check for a single wire going somewhere along the frame. If that's loose, you'll get an inaccurate gauge reading.

is it a wire from the guage itself, or from something else?

usually, it comes from the gas tank itself going somewhere along the frame.

thanks