If you have a fresh set of plugs, try them after you clear the codes and do a compression test. How many miles? Let us know the compression numbers. The image appears to show a direct injection motor. The M54 has the injectors farther up the intake manifold. Is it oil on there or does it smell like gasoline?

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2001 x5 3.0 (sold with broken motor), 1990 e30 M3, 1991 318is, 2002 325i, 2008 335i Dinan stage 3 6 speed,