[sigi77]

2007 N53 engine

Long story short: Replaced mosfets after code 30BA came up, by an expert in the city. 100% he was doing the work good, as i seat next to him, and i am familiar with electronics.

The engine was also full repaired by technician: cylinder-head gasket, oil gasket, timing chain.

I gave him 6-6 Gasket rings: 13537584315, and the decoupling metal elements.
Drove 250km-s without a problem, and soon check engine light came up, also started blinking. Fuel consumption went very high, we had to stop at a station. (100km fuel in 10km...)
Big smoke was noticeable from the engine intake part also.

29E0:mixture control
2A2B:mixture control
29CD:Misfiring, Cylinder 1
29CE:Misfiring, Cylinder 2
29D0:Misfiring, Cylinder 4
29D1:Misfiring, Cylinder 5
29D2:Misfiring, Cylinder 6
2AAF:Fuel pump, plausibility
29D9:Misfire at low tank level
29CC:Misfiring, several cylinders
2C78:Lambda probe downstream of the catalyst 2, Signal
2C7C:Lambda probe downstream of the catalyst 2, Signal
2C7B:Lambda probe on the catalyst, signal

HPFP: 1 years old, was brand new. changed already.
Cylinder 4,5,6: new injectors. (changed less then 12 months, and no.6 is brand new)
4 o2 sensors (pre, post) brand new.

+ info: He told me that he changed the injector gasket rings (o rings) by putting them on, and giving some heat. As i know this is not the proper way. Can this cause a serious issue like above? If yes, what to do now? Can it be repaired or i need to buy 5 new injectors? Any other problems i should worry about?
Any help, or things to check would be appriciated.

[sigi77]

So actually the Cylinder 5 misfire is the problem, after injector replacment, it came back after 70kms.