On my 03 250 5.4 with 82K, I get between 12.5 & 14 on the hwy between 60 & 70. I have gotten it to hit 15 running about 60 with the cruise set as well. I run about 55mi one way 5 days a week. We just did the tune up, ball joints & shocks all the way around.

If you are going for fast acceleration, the 5.4 sucks!!! It is a grandpa's truck when it comes to getting up to speed. If you are wanting faster acceleration you are going to just be wasting gas in it. I can tell when my hubby drives it cuz he accelerates like he is in our jeep......kills my mileage.