if the fuel sender is unplugged then it wouldn't cause a problem, you just won't know if your about to run out of fuel
i had the same problem myself (there's another thread somewhere in this section)
the conclusion i came to is my fuel sender is fu*ked as the reserve switch is ok when tested, so until i see a cheep one on the bay i'll continue to count the miles or in my case Km, 180Km then it's time to find a garage