N54 - Misfire idle and mysterious vibrations in 1600-1700rpm in low speed and high gear


New Member
Oct 1, 2023
Hello there !
I have E92 335i N54 with DCT, modded to stage 2+ with all supporting mods ( over 5 years ).
Month ago i was traveled with car to long trip vacation with my 335i, so after we went back from vacation.
- My car start to misfiring on idle, so i put new sparks NGK 97968 with gap.
The vibrations have stopped a bit, but they was still there, so i get angry and changed to Stage 2 LPFP, with EKPM3 module, all of index 9 and mis-mas-ch set of injectors, to brand new index 12 injectors, properly coded.
And im still not getting on bank 2 AFR 234.94 after Index 12.. can you please somebody check out my logs? I will be very happy, because i cant find anybody near me, who know N54 problems.
I will post Datazap logs from MHD.
a) Cold start with Index 12
b) MHD Stage 2+ Index 12 - 2500rpm 3. gear WOT
c) MHD Stage 2+ Index 12 - 2700rpm 3. Gear WOT
d) MHD Stage 2+ Index 9 and mix of injectors 4. Gear WOT

- On datazap i have sortage of MHD, DocVu and new Index 12 Injectors on Stage 2+

Can somebody checkout the new index 12 logs please?
- Why im not reaching a 234 AFR? and why i get drop when i start cruise from idle to 500rpm please?
- Why i feel some sort of vibrations from engine? - like misfires on 1500-1700rpms? if im in above these rpms its running without vibrations. This only does if i have selected D on trans. Because the trans shifts at this points.

THX So much for everybody!



Jul 7, 2020
07' BMW 335i
Have you scanned to see if you have any codes? I'll take a look at those logs tonight when I can get to my laptop...hard to navigate the dazap logs on a cell phone.

A few questions. What did you gap the plugs to? How old are your coils? I'm assuming that with misfires, you are getting misfire codes? What cylinders? Have you tried moving the coils around to see the misfires follow the coils?

Also, why did you throw a stage 2 LPFP and all new injectors at it? Were you logging fuel pressure issues? ..or were you just shot-gunning parts at the car hoping something would fix it? That's a lot of money right there in parts......

Also...have you done a compression and leak down test? If not, I would start there. You could have a burned valve or cracked piston. Not all that rare.