My fuel guage reads full, almost empty, or sometimes it seems to work normal. I did some checking and see that this tends to be quite a common problem with these trucks. The question is- Is it a matter of cleaning, scraping or polishing the fuel sending unit, or do these things have to be replaced. Is there any type of fuel treatment that would help these things. It doesn't seem to be a big job to take apart but any tips would be appreciated. Thanks