fuel gauge problem

My Daughter,has a 2006 ford five hundred, that some times doesn't show that I put any fuel in it,or show no fuel in it. It doesn't happen evey time so the mechanic says they would be shooting from the hip.Any help in this matter would be great. Thanx

Hello,
I am manish solanki (http://manish2010rakhi.wordpress.com) from India. now We in fuel problem because in this time nobody carrier of this so please no wast fuel
used toyota landcruiser (http://www.usedtoyotalandcruiser.com.au)--used toyota landcruiser

My Daughter,has a 2006 ford five hundred, that some times doesn't show that I put any fuel in it,or show no fuel in it. It doesn't happen evey time so the mechanic says they would be shooting from the hip.Any help in this matter would be great. Thanx
My 2005 ford five hundred has similar problem. Anyone have any ideas as to how to solve this problem?
Thanks in advance,
Rog.