carl heath

hi i need to test my injector(swap 2 + 4 over ) on my 02 sti and wanted to know if there was a how to do it link on here or if anyone can tell me hows easyest way to do it,im getting 0304 code missfire on 4,have changed plugs and swapped coil to no avail.subaru have said maf but just tested with multimeter and got yellow wire on right-12.53 ignition on,14.10 idle,14.10 with revs....... green wire -middle,0.72 ignition,1.26 idle,2.3 with revs........ blue +white wire second from left,2.88 ignition,3.16 idle,no change with revs, the other two wires hardly show any figures,obviously need to know what readings should be,have sent pm to simon at jgm but not got back to me yet.any help will be much appreciated as doing my head in and want to rule out injector,as have ruled out plug and coil,supose i can do the ignition lead too.

carl heath

any ideas or any body have readings or output of maf on 02 sti