[sa6o4dnb]

Hello, recently i bought a e92 2007 with a n43b20 engine. When i got the car, it was running a bit rich with a slight puff of black smoke on hard throttle. I could also smell petrol on cold starts in the cabin and it as idling bad and hesitating on acceleration. When i took the spark plugs out i noticed that 2 of them, on cyl 2 and 4 are black and smell like petrol. So for me it was obvious the problem is in the injectors. I changed the sparkplugs anyway, but there was no difference. Next step was to get some 2nd hand injectors. I know the best thing is to put 4 new index12 injectors, but they are expensive, so i decided to take my chances and bought 2, 2nd hand index9 injectors from Ebay and new teflon seals. Changed the 2 injectors with new seals, the one on cylinder 4 was definitely bad, it was covered in muck, and i can see a hole on the tip. I have also coded the values of the new ones with INPA.

There was no more black smoke, no matter how hard i rev the engine. The smell of petrol on cold starts is gone. But the stutter on idle, and the hesitation is still present. When i check the live data on Inpa (i dont have much experience with the software) i can tell that te O2 sensors are working correct. I drove the car for a few days like that and it seem to get a bit better
but there is still vibration and hesitation. Fuel terms, before the change were on -10,-20 on both banks on short and long, now all of them are on +-5, except long term bank 2 witch is around -15,-20. There were some error codes previously for a rich mixture witch i erased. Now i checked for error codes again. There were 2 codes

30DA nitrogen oxide sensor
OBD debounced
30C1 Engine oil pressure control, static
pressure too low

Both codes were not present, and i never seen them before. i dont have MIL as well, but when i put the new injectors i have started the car before coding them to watch for fuel leaks. i have deleted the codes now, but the engine starter to run even worst immediately after deletion. I drove the car around the neighborhood a little no codes appeared, there is no smell and no smoke, but i can feel the engine is not running right. also, when i listen to the injectors, they seem to change their clicking on idle, like they run on one pattern for a few seconds, then they change the clicking for a moment and they revert again.

What should i do next, if there is a better way to diagnose using INPA that someone can explain to me, i have watched a lot of videos and read threads, but its like my inpa is different somehow, i do go to MSD80 section so should be the same but....

Any opinions and suggestions will be a help to me, Thank you.