[jeffro535]

Need an opinion since I'm relatively new to N54's: the car was was at the dealer for almost a month in an effort to fix the year long hesitation/stumble/rough idle problem. I won't bore everyone with the details, but what stands out to me in the paperwork is they walnut shelled the valves due to heavy carbon buildup on cyl's 5&6. The car was walnut shelled last May (about 8k miles ago) and it was noted then that cyl's 5&6 had a heavy build up. I do not baby this thing and none of the other valves had any build up. When it went through a round of misfiring badly on cold starts awhile ago, the first time it flagged 5&6 and the second time it eventually flagged all but #2. Compression and leakdown tests are normal. The only thing I can come up are the intake valve guides are letting oil through, though there's no visible smoke and oil consumption seems normal. I does tend to do the rough idle more after I downshift while slowing and use engine braking. I'm open to ideas here. The dealer is saying the next step is the DME, then the DME harness, but to me the physical evidence seems otherwise.Thanks for any input