misfire detected

[radek00]

Hello
A friend of mine has a BMW E87 with an N43B20 engine and has a misfire problem. The car sometimes has power, but sometimes it noticeably loses power. Occasionally, it stalls while idling. No errors appear. I once had a DTC 2a26 "Catalytic converter, conversion in stratified charge mode" error, which appeared after resetting the engine adaptation and driving about 50 km. The injectors, coils, and spark plugs were replaced – the mechanic did all of that. I also replaced the engine wiring harness, unfortunately with a used one. Perhaps someone has experienced this problem and could offer some insight. There are no misfire errors, but they are visible when connecting the app to my phone, and most often, it's on cylinder 4.

[ek1978]

IMO , only a good Mechanic can help you.
My advice : don't put too much hope on online forums when it comes to such Problems , it might cost you more than you what you need to pay.

[Stratofortress]

New or used injectors installed, PCV confirmed intact and HPFP working accordingly?

[radek00]

From what I know, two of the injectors are original BMW ones, and another two are probably Vitesco ones. When I looked at the actual readings, the high-pressure pump was idling at 150 bar.