airbus and boeing problems

I'm using the default planes. The airbus I'm doing a long flight and I notice that the fuel is depleting only in the left wing, and not evenly causing center of gravity problems, not to mention my left engine ran out of fuel. Does anyone know what the problems is? My other question is on the Boeing 737 in mid air the engines cut out saying low oil pressure hit ctrl+ E and there back to normal, any suggestions?