I fill it up, and I drive it around, it could be full it could be a half a tank, it only moves maybe under the line an 1/8 of an inch, then sometimes it'll go above the line the same amount, and when I park, I come back the next day and it's much lower than before, I guess that's my true fill. But sometimes it'll slowly go up about an 1/8 of a tank or 1/4 before it stops and starts reading the gas again. I can't tell if it's sticky or if the sending unit is bad, I don't think it's the sending unit from what I've read of other people's problems. Any help would be great, thanks!