Gasoline Mileage improvement after break in.
This is the first vehicle that I have ever owned, and I have owned many, that actually improved its fuel mileage a lot after the first 5,000 miles. It is a Silverado 2500HD with the 6.0 gasoline engi...
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My GM 6.0L steadily improved over the first year/21k miles. I got it in October and got about 12mpg all the first winter. Took at 2600 mile trip starting at 6500 miles and got 15mpg. 7 months/10k miles later took a 1000 mile trip and got 17.7mpg. And now I can get as high as 20mpg @ 65mph non towing. I'm very impressed with the combination of performance and fuel efficiency.
