Well I guess my gage works o.k. I mean it shows full when I fill up and empty when its empty.
[highlight]But what I have trouble understanding is why I get great gas milage from the top half of the tank (140 mi.) and such poor milage from the bottom half(25 mi.)?[/highlight] :-/
I have no fogging yet 5400 mi. and caught in fair share of rain.
Must be speeding up to make it to the gas station before you run out?

Actually, most of the gauges work similar to yours, only not quite as non-linear. Before I modified mine, I would also get about 140 miles by the time the gauge hit 1/2, and if I stretched it to almost empty (5 gallons to fill) I would show approximately 180 - 190 miles with the gauge still sitting above 1/8 and the light just coming on. Now mine hits 3/4 at approximately 60 miles, 1/2 at 100 - 105 miles, 1/4 at 140 - 150 miles, and the light comes on at 3/16 (1.0 gallon remaining). It still sits at full for the first 50 miles, then drops suddenly to 3/4. As long as it is reasonably accurate on the second half, that's all that matters to me. At least it is consistent, so now I have no qualms about leaving the odometer set on total mileage rather than the trip mileage, and just going by the gauge. When it hits 1/4, it's going to take approximately 4 gallons to fill (5.4 gallons is total capacity, from bone dry to the little holes in the filler neck).
Jerry