Fuel missfire

Got my gtir taxed and insured.but having a massive missfire at idle.running and sounding like a scooby.
No 4 cylindar is not running properly.sparking ok but no fuel going in.checked the injector works ok.even swapped with known good one.
On further investigation getting 12v too all injector both side of the harness plug no 1 2 3 on white coloured wires are being switched to ground and working fine.
But no 4 is not grounding properly.have done continuty test and from resistor pack to injector wire is fine. Any help would appreciated

Thanks zia

Totally guess Ecu related then. What Ecu did you say you were running or changing mate ?

Yeah if I'm nit mistaken injector earth is controlled by ecu. Check you wiring from ecu to injector first before bining ecu...