I filled up my 96 2wd Sierra on Saturday. Monday, I went to take kids to school, and noticed that the needle was pointing south, like to 6 on a clock. My driveway has a small slope to it, nothing major, and it was pulled into the driveway with the back end lower. As I drove the kids to school, the needle was all over the place. It went down when I accelerated, and back up when I slowed or stopped. I went all the the way to E back past F. Today, its a 3/4 full, and isnt moving at all? I am not trusting this darn thing in any way..lol I mentioned it to the ol man who said something was lose and floating around in the tank, (he told me and I forgot what its called, and refuse to say floaty thingie). Which made sense, but if that is the case, why isnt it still erratic? It almost fixed itself, or now its just stuck, not sure which? Do I fill it up and see what it does again, or take it to E and let a mechanic look at it?