94-940 fuel guage quirk-my 94 940 the fuel guage reads when it wants to-goes to empty when it wants and come back on when it wants -the low fuel light always works. i tightened the screws on the cluster -i have been told by one mechanic its the sender in the tank but why does the low fuel light work ok and the guage works all day sometimes and others it doesn't read-think i should try a diff guage or diff cluster or is it the sender in tank -can it be repaired ? no fuel problems 109k mi