While on the same issue, I have a related question - should one change oil less often if one does more highway driving? I change it religiously after 3000 miles when I have been driving in the city/suburbs. But this time, out of the 3000, 2000 was highway (long stretches) - should I still change it at 3000, or go till say 4000? Basically, does the oil quality deteriorate as much by highway driving as by city driving?

thanks!

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