We did not see a significant improvement in the mpg on our 08FEH until just after 9,000 miles.

At just over 9k, we had our first oil change done. We used 5-20 fully synthetic oil.

Not long after that, our fuel mileage increased without changing our driving pattern or habits..

We consistantly get 38-40mpg in our 2wd Feh. Other than special trips, ALL of our driving is done on roads 40mph or less.

On a recent trip to Miami (200 miles each way) we averaged 36.6mpg all highway 65-70mph.

The weather has been cooler due to winter, we have been using the AC less, we haven't stopped using it however.

When we first got the FEH, we took a trip to Daytona and were only able to get the advertised 30mpg highway.

Improvement in your mileage will definately come.

I am not sure of the reason(s) for this improvement exactly.. but I am VERY happy with the end result. Since the increase we have never gotten less than 500 miles from a single tank and got just over 600 one time when I somehow got almost 17 gallons to fit in there. I still have not been able to get that much in, or get that many miles since.

hope this info helps..

08FEH