I have a 06 4.8is with 37K miles. I calculate my MPG every time I fill up. I constantly get about 350 miles on 23Gal of premium gas. That’s around 15.2 mpg. I don’t push the car hard, no hard acceleration but I do warm up the engine. I do mostly highway driving with low traffic grid time.

I don’t understand how some of the guys are claiming 19mpg on 4.8is. I just don’t see that….