[jpregione]

2009 328i N51 engine, AA headers / tune, charcoal filter removal / k&n filter, catback exhaust, 55,000 miles. About a week ago car starting running like crap and SES came on, pulled over turner car off / on, SES went off and all was fine. Today son drives the car and tells me its misfiring, pulled the code and misfire cylinder 6. I decide to swap coil packs between 1 and 6 to see if it moves, while i'm there I decide to pull the cylinder 6 spark plug. Plug looks like poop and gap is 0.066. I'm like WTH, so I pull all the plugs and they are all BMW OEM Bosch, gap set to 0.066. Luckily I had ordered NGK's a few weeks ago and decided now was a good time to swap. Verified gap was 0.044 ish, put everything in and it seems to run smoother with a little less hesitation. Has anyone seen this before? I did a search to see if the high gap was part of BMW sulev master plan but haven't found anything. Any help / thoughts would be great....

[Mike.]

I had this same problem but my plugs just went bad around the same time yours did. I didnt notice the gap. If this was part of their master plan, I think someone would have already noticed

[jpregione]

I agree, and I haven't been able to find any other posts on the subject... its just odd that all were the same gap...

[Eagle1oh7]

I never had a problem after I swapped my plugs with NGK. Strange, where did you get them? I got my set from TMS, so perhaps they already came gapped appropriately?

[jpregione]

The plugs that had the wider gap were already installed in the car, they are labeled bmw bosch and given the car only has 55k and nothing else has seemed to have been done to it I assume they are the original ones. I installed NGK that I ordered from amazon... they came pre-gapped at ~ 0.044.

[Three_thirty_I]

If it's anything like the N52 plugs, then they should be pre-gapped, and iirc the Bosch plugs for the N52 have a 1mm gap. I dug out my feeler gauge and they were all exactly 1mm before I went along and fitted them.