2012 Toyota tunda 5.7l v8 with 35,998 miles (2 miles left on warranty). First cold fall morning starter did an extended crank and had rough start- felt like an old car with bad points even though it's an efi. Called dealer in Ames iowa. They adjusted fuel density setting on computer and honored warranty ( it was 200 miles over warranty by the time of appointment- great so far). I asked and they stated this was a rare issue and have never seen a need for second adjustment.

Update from Dec 13, 2014: 12/10/14 40,200 miles. After computer changed density setting mpg dropped. I reset on dash setting every oil change and change oil per recommendations of 5000 miles. My driving habits are a stable 75% hwy 25% city. Gas mileage of 16.9 mpg dropped to 15.5. I called the dealer and was politely told I'm an idiot and that's not possible. fall stayed warm after repair and I park at home in 60 degree garage. On 12/4/14, it was cold and I had the same extended crank hard start issue after work. I saw a large plume of white smoke coming from exhaust upon start and didn't take notice as it was cold. The same dealer in Ames iowa was called and I scheduled routine oil change and look at hard start issue.

12/12/14. They readjusted density again and told me that a Toyota bulletin was released on 12/11/14 recommending a 1/2 day service which I need to schedule. Cost $0. They stated that they will cover identical warranty issues for 1 year even if traditional warranty is expired. I was informed that my oil was "a little low". This is my third tundra. 2008, 2011, 2012. I've never had a drop of oil loss even when 2011 tundra was hit head on by a drunk driver in a ram 3500 going 100mph and the tundra motor was crushed I had to turn off the motor!

I'm suspicious of sudden oil consumption. Gas mileage has increased to 16.4 which is better than first density change. I'll update later