Originally Posted by themyst
James, valve cover gasket maybe?
Especially if you're seeing buildup on the plug electrode or threads.
Possible but doubtful. Car only has 36,500 miles, but is a 2008 build. No leaks, nothing else funny about it, all stock. It's out of warranty now, so thankfully he didn't take it to the stealer.
I think the sooty buildup is poor fuel combustion, not oil. The piston crowns look pretty clean on large portions, and they look relatively the same across the 4 out of 6 I looked at. The plug is sooty around the area that is directly adjacent to the injector. I'll shoot some photos.
If this doesn't work tomorrow, we will have to pull the intake and/or do some leakdown testing.
E92 335i/6MT Dinan Stage 3: intercooler, oil cooler, intake, flash, exhaust, LW dual-mass flywheel.
Vishnu PWM methanol custom trunk mount, Diffsonline 3-clutch Salisbury custom diff, Ohlins Road and Track coilovers, Vorshlag camber plates, much more...
E28 M5 w/ buncha stuff, R171 SLK350