From my experience, it probably
is the sending unit. There really is not much involved in the whole thing, and there is little else it could be. Price the sending unit, and see if it is in your price range. They are fairly straight-forward as to replacing them. Buy a FORD Factory manual, and you should have all the information you need. Stay away from the Haynes/Chilton brand manuals. They seem to always be missing whatever particular information you're looking for.
Good Luck.
Don't forget to check the net for parts. Sometimes you can get a good deal on one, or even a slightly-used one.
