Better Oil consumption?

I was told to change carburator Injector to get better oil consumption,is it really worth changing?

As i am getting only 4miles per litre petrol on average with my car ( Vaxuxhall Corsa 1.4 Ls automatic transmistion,96 yr reg).
Can any one tell me to improve my oilconsumption.It has been serviced recently changed all air,oil filters spark plugs though.