[Exotic_Tastes]

To add to what CATAHA said, I believe the official BMW recommendation was to change the entire bank when replacing injectors on the N63 and N54 engines. I would start with changing out injectors on cylinders 5, 6 and 7 then reassess. Alternatively, I believe there are some shops available online for testing injectors at a low cost, but I have not used any personally.

Are you covered by the N63 recall campaign? You could call your local dealership and ask if there were any warranty extensions or log into BMW's AOS/TIS and check for Service Bulletins. In the US, the N63 engines were covered by additional warranties due to lawsuits.

With this generation of injectors, they were engineered with a poor failure mode, as the fuel sprayer extends outward. They are very prone to leaks, which causes rough idle at the early stages of failure and can cause hydrolock the engine if left unaddressed. One thing to remember is that when a part is weak or failing, other components tend to compensate. I vaguely recall seeing abnormal values on multiple cylinders then ended out changing all injectors that weren't recently replaced once I did my valve seals and then my engine ran perfectly. The N54 and N63 were essentially good engines with bad parts, which can make them a headache to maintain.