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Pontiac G8 GT Real-World mileage
I'm still breaking-in my G8 GT but just finished a trip. With just under 2000 miles on it, I managed 26.5 mpg on my last tank with an average speed of 67.5 mph. This was over some hilly terrain in Southern VA, NC, and SC (I-77/I-26).
That's a little slower than I normally drive (break-in) but I'm still very impressed. I'm eager to see if the mileage improves after the engine is fully broken-in.