We are just about to hit 10k on our FEH. We recently changed the oil and instead of using the recommended 5-20 synthetic blend, we used 5-20 premium synthetic (motorcraft). There have been a couple of significant differences in the way our FEH is performing. I have gone about 200 miles since the oil change.


First, the transition from ev to ice is significantly smoother. This might sound crazy, but there is a noticeable difference.

My fuel mileage has increased SIGNIFICANTLY....

Could this be due to just the oil change or could there be a change in the way the truck performs at 10k?

We have not changed our travel routes, we are not hyper anything.. We are driving the truck the way we always have. 99% of our driving is rural, straight, flat roads with a max speed of 55, most roads are 35 however. The weather has been high 60's to low 80's and dry.

We normally average about 34-36mpg..since the oil change, we are averaging 42-43... (it has been as high as 46 but no lower than 42).

Now to add another twist to the story, On my last tank of fuel, I ran the truck to 0 miles to empty (but not out of fuel).
I wanted to COMPLETELY fill the tank, so at the end I patiently held the nozzle at a slow rate until it could take no more. I could see fuel in the neck when I removed the nozzle.

The slip said 16.235 gallons!! Is this possible in a 15 gallon tank (per owners manual)?? Could this station be over charging?

The kicker is, I have gone 106 miles since filling up and the miles to empty says 531. The fuel guage is still pegged on F. Could the float be stuck in the tank or something?

The avg right now is 42.3 and we always reset just after filling. So it is a 106 mile avg.

Help me understand some of these changes!

AM I GOING TO GET 600 miles out of this tank???


08FEH

So far on my 08FEH at 1300 miles the best I have been able to do is 30.8 MPG on the current tank. Unfortunately my driving pattern involves lots of hills and short cold runs, but at least it is better than the 20MPG that I used to get on my Cherokee. Contrary to the advertised performance, I get better MPG on the freeway than I do in the "city."


I think your high MPG has to do with the land. I don't think anybody knows why there is an improvement after break-in.

My comments in red.

-John