There should be a code. I wonder if this point you have cylinder wash?...gas washing the oil seal off cylinders? Have you had a bunch of cold wearher? Does it sound like low compression?

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'03 530i - manual swapped - 425k miles
'06 325Cic auto 115k
'05 X5 3.0 auto 158k
'99 E39 528i 5-speed 130k