Sorry, that wasn't clear in the post. It cranks very well at all times but sometimes won't start. And, not to sound cynical since I sure don't know the particulars of this car, but since it does crank, can we rule out the
N-safety switch? Also, the O2 sensor part doesn't make sense to me. The ones I've seen go bad (on American cars) won't keep it from starting but will make it run poorly once started. But, I'm not well-versed on the Benz so I'm sure gonna listen (gratefully) to any suggestions.
Thanx, Chuck.