1:no haven’t checked fuel presssure 2:yes connectors were installed properly and no vaccum leaks 3:I’m not sure what 12v ground off is 4:yes all injectors ohm in spec 5:I don’t know how to do the leak check 6: yes it would shake and misfire due to 3 bad injectors 7:no 8:they were used injectors And Only cylinder 4 is being flooded by fuel