This is the third UOA that I've done on this 2008 Chevy Trailblazer SS since I purchased it used almost two years ago. The first UOA was using Mobil1 5W30 and the most recent two were using Pennzoil Ultra 5W30. For all of the samples I have been using K&N HP-1017 filter. Only modifications to the truck are an IEATSRT8 CAI (which uses an S&B cone filter) and PCM4Less tune, both of which have been present throughout all samples. All samples were collected from the pan at the time the oil was drained (and changed). I'm somewhat concerned about the fuel dilution issue that has shown up in this most recent analysis and will probably re-test in the next 3000 miles or so to see if anything has changed. Some notes: This vehicle is one of my daily drivers and sees the bulk of its driving duty in the Fall-Winter-Spring months. Occasionally it will sit for up to a week during the summer time without being started. Fuel mileage has been consistent since I've owned the truck. My commute to work is ~30 miles each way with all but maybe 2 miles being highway. I would say that my driving is 80% highway/20% city. Average speed on the highways around here is between 65-80mph. The engine runs great and shows no signs of running rich, etc. However, I do not yet have a wideband so I can't monitor actual A/F. I am planning on upgrading my HPTuners here in the near future to add that capability, though (I have the old standard MPVI).