Quote Originally Posted by oleshifty View Post
Software I have for truck monitors gas mileage. Even with the lift, at 45, i get about 22 cruising.

75 is pretty fast for 'good mileage'...current setup I don't see past 12 at 75 unless I'm bumper to bumper with a semi. I don't see past 17 at 55.
Your software was most likely off which is normal when you start modding an engine.

The only way to measure fuel economy is manually log the mileage and amount of fuel consumed. Sorry, but you didn't get 27 mpg unless it was for only a couple miles downhill.