SarTech:

Where did you ever end up with your misfire codes?

I am having a similar issue, although my misfire (P0300 through P0306) codes are not accompnied by any other codes, and only seem to occur when off the throttle at highway speeds or very little throttle at highway speeds. Occasionally they will get thrown at lower speeds.

I have replaced every sensor, smoke tested the engine intake and exhaust 3 times, did a compression test (all within 5%), and still have the issue. The truck runs great under load and at idle.

Pulling my hair out! I love this truck, but I think it soon needs to go...

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2006 X5 3.0i 6MT
2004 ///M3 Coupe 6MT
1997 ///M3 Coupe 5MT
2015 X3 2.8i xDrive