Nissan Largo Friends

hi all

Am Rajai from Newzeland arlborough, my nissan largo highway star keep flashing check engine light
and after check the code number is 18 fuel injection feedback system2.
i do need help to know what the fault there

many thanx

Check the plugs on fuel pump.

im gettin that at the mo if im doin 80-90 mph if slow down to 50 ish it goes off

what sort of mpg are you getting at 90mph ?