Just a few weeks ago I took a 1000 mile trip in my 04 Silverado and burnt a qt of Mobil1. It did look and smell skanky when I checked it. I have been using Mobil1 consistently since the 80's and have had a few spotless motors with over 100,000 miles. Never has this happened before. I dont what to think, I'll be changing the oil on tuesday. Will continue with the Mobil1. I'll ask my people at Mobil if they have seen this problem.
