As voters in Nigeria ready themselves for the Feb. 25 presidential and legislative elections, consumers in Africa's most populous nation are facing fuel and cash shortages. At a fuel station in the commercial capital Lagos, tempers flare and harsh words are exchanged as motorists wait in line for hours to fill up their tanks at one of the few outlets with petrol left in the area.  There are also not enough new banknotes because of a central bank decision to replace old notes with new ones to curb cash in circulation and control double-digit inflation.