My 280mm sender reads a bit erratically but generally gets towards indicating 0% after about 200 miles from filling. In that sense, I wouldn't say that the 280mm sender is any more or less accurate than the original 250mm unit, it just shows 0% with a more realistic reserve, rather than half a tank as the original one did. If yours is showing % numbers all over the place it must be down to a faulty sender or possibly a chaffed wire or bad contact, not easy to find. Does it behave the same with the old 250mm sender refitted?
