N55e (PWG) New Plugs, Lamda, Major Misfires?!

[The Sasquatch]

Hi All,

So after a rough idle I plumped up the courage to pay for a new official BMW (winces) pre-cat O2, and BMW plugs. These were fitted by a good local garage. Then also replaced the MAF with a VDO Continental (OE brand) sensor. Car ran very well. So, after a day or two of driving and sure that everything was operating well I flashed it to stage 2. Put my foot down and BAM, the worst stuttering misfire I have ever experienced. I then flashed back to stage 0 map again but the misfire at anything over half throttle is still there. Smoke tested the car today. No leaks. I’ve added the log of the car misfiring when I prod the throttle. The car also threw half a dozen misfire (cylinder 6) codes.

Any ideas what is wrong here?!

Datazap of misfire log

 

[wheela]

Did you check that all your coils are still fully seated and your plugs tightened to correct torque? I had a misfire that would only happen above part throttle, and I discovered the coil over the trouble cylinder wasn't fully seated on the plug. So current could jump the gap from the coil to the plug and have enough voltage left to ignite the cylinder charge up to part throttle, but higher load it would just misfire. I also noticed that plug was loose, so I suspect some combustion gases may have popped the coil loose. I did put on all new coils because they were old, but I suspect just re-seating the stock coil would have fixed the misfire.

 

[The Sasquatch]

Thanks so much for the response. I’ll take a look at re-checking the plugs and coils and report back! The gases lifting the coil sounds very plausible. I wonder if this is the case it might suggest the injector on cyl6 is leaking?