rix166,
Another possibility is when a cam oiler tube pops off, the valve cover slowly floods with oil and then the intake guide suck the oil into the combustion chamber. This would take the 1 to 2 mile drive for this to occur. The oil fills the rear of the cover and overloads the intake seals. Oil would be noticed on the rear spark plugs of the affected bank. Additionally this car did not smoke at cold startup.

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Paul