While there are many potential reasons for a misfire, or missing, the following refers only to situations caused by fuel.

AKI refers to the resistance of the fuel to ignition, or rather uncontrolled ignition, also called predetonation. A fuel with a higher octane rating will be harder to ignite. That is a good reason to have high performance ignition systems on race cars. On a modern street car, the problem usually only shows up in cold weather, when the engine is cold; the engine can misfire, or miss. When the piston compresses the mixture, and the sparkplug does not ignite that mixture, that is missing. It can happen on one or two cylinders, usually until the engine is at operating temperature, or at least partly warmed up. The BMW fix for this is to advise the owner to move to 89 pump octane until the weather warms up. This is not a problem in Southern California, but not all of us live there.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue